New intro, images, and links (#18610)

* Update content and links in Readme

* Add explainer to dev machine setup

* Update README.md

* Update README.md

* Update README.md

README.md

@@ -1,22 +1,20 @@
-# [![Mattermost](https://user-images.githubusercontent.com/33878967/33095422-7c8aa7a4-ceb8-11e7-810a-4b261fdff6d6.png)](https://mattermost.org)
+# [![Mattermost](https://user-images.githubusercontent.com/7205829/137170381-fe86eef0-bccc-4fdd-8e92-b258884ebdd7.png)](https://mattermost.com)
 
-Mattermost is an open source, private cloud, Slack-alternative from [https://mattermost.com](https://mattermost.com).
+[Mattermost](https://mattermost.com) is an open source platform for secure collaboration across the entire software development lifecycle. This repo is the primary source for core development on the Mattermost platform; it's is written in Golang and React and runs as a single Linux binary with MySQL or PostgreSQL. A new compiled version is released under an MIT license every month on the 16th.
 
-It's written in Golang and React and runs as a single Linux binary with MySQL or PostgreSQL. Every month on the 16th [a new compiled version is released under an MIT license](https://www.mattermost.com/download/).
+<img width="1006" alt="mattermost-hero" src="https://user-images.githubusercontent.com/7205829/136107976-7a894c9e-290a-490d-8501-e5fdbfc3785a.png">
 
-- [Review product documentation](http://docs.mattermost.com/).
+Useful Resources:
-- [Review developer documentation](http://developers.mattermost.com/).
-- [Download compiled version](https://mattermost.com/download).
 
-<img width="1006" alt="screenshot at nov 29 14-11-32" src="https://user-images.githubusercontent.com/13119842/56807911-1bf66f00-67fe-11e9-9b7b-96ce9ceab645.png">
+- [Deployment Guide](https://docs.mattermost.com/guides/deployment.html) - Install, setup, and configure your own Mattermost instance.
+- [Admin and User Documentation](http://docs.mattermost.com/) - Learn how to run a Mattermost instance and take advantage of all the features.
+- [Developer Documentation](http://developers.mattermost.com/) - Contribute code to Mattermost or build an integration via APIs, Webhooks, slash commands, Apps, and plugins.
 
 Table of Contents
 =================
 
   * [Try out Mattermost](#try-out-mattermost)
-  * [Deploy on Heroku](#deploy-on-heroku)
+  * [Install Mattermost](#install-mattermost)
-  * [Deploy on a Cloud Platform via Bitnami](#deploy-on-a-cloud-platform-via-bitnami)
-  * [Install on Your Own Machine](#install-on-your-own-machine)
   * [Native Mobile and Desktop Apps](#native-mobile-and-desktop-apps)
   * [Get Security Bulletins](#get-security-bulletins)
   * [Get Involved](#get-involved)
@@ -29,22 +27,23 @@ Table of Contents
 - [Join the Mattermost Contributor's server](https://community.mattermost.com/signup_user_complete/?id=codoy5s743rq5mk18i7u5ksz7e) to join community discussions about contributions, development and more
 - [Get started with Mattermost Cloud](https://customers.mattermost.com/cloud/signup) to try out Mattermost
 
-## Deploy on Heroku
-
 [![Deploy a Preview](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/mattermost/mattermost-heroku)
 
 _Note: Heroku preview does not include email or persistent storage_
 
-## Deploy on a Cloud Platform via Bitnami
+## Install Mattermost
 
-[Auto-deploy Mattermost](https://mattermost.com/download/#bitnami) to Amazon Web Services, Azure, Google Cloud Platform, or Oracle Cloud Platform via Bitnami.
+- [Quick Install Guide](https://docs.mattermost.com/getting-started/light-install.html) - Deploy in minutes via Mattermost Omnibus on Ubuntu.
+- [Run Mattermost via Docker](https://docs.mattermost.com/install/setting-up-local-machine-using-docker.html) - Launch a Mattermost server instantly to test functionality and build integrations.
+- [Developer Machine Setup](https://developers.mattermost.com/contribute/server/developer-setup) - Follow this guide if you want to write code for Mattermost.
 
-## Install on Your Own Machine
+Other Install Guides:
-
+- [Ubuntu 20.04 LTS](https://docs.mattermost.com/install/installing-ubuntu-2004-LTS.html)
-- [One-line Docker Preview](http://docs.mattermost.com/install/docker-local-machine.html#one-line-docker-install)
+- [Kubernetes](https://docs.mattermost.com/install/install-kubernetes.html)
-- [Developer Machine Setup](https://developers.mattermost.com/contribute/server/developer-setup)
+- [Helm](https://docs.mattermost.com/install/install-kubernetes.html#installing-the-operators-via-helm)
-- [Production Install Guides using Linux Binary](https://mattermost.com/download/)
+- [Debian Buster](https://docs.mattermost.com/install/install-debian.html)
-- [Production Docker Install](https://docs.mattermost.com/install/prod-docker.html)
+- [RHEL 8](https://docs.mattermost.com/install/install-rhel-8.html)
+- [More server install guides](https://docs.mattermost.com/guides/deployment.html)
 
 ## Native Mobile and Desktop Apps
 
@@ -56,17 +55,14 @@ In addition to the web interface, you can also download Mattermost clients for [
 
 Receive notifications of critical security updates. The sophistication of online attackers is perpetually increasing. If you are deploying Mattermost it is highly recommended you subscribe to the Mattermost Security Bulletin mailing list for updates on critical security releases.
 
-- [Subscribe here](https://mattermost.com/blog/category/security-updates/)
+[Subscribe here](https://mattermost.com/security-updates/#sign-up)
 
 ## Get Involved
 
-- [Contribute Code](https://developers.mattermost.com/contribute/getting-started/)
+- [Contribute to Mattermost](https://handbook.mattermost.com/contributors/contributors/ways-to-contribute)
 - [Find "Help Wanted" projects](https://github.com/mattermost/mattermost-server/issues?page=1&q=is%3Aissue+is%3Aopen+%22Help+Wanted%22&utf8=%E2%9C%93)
 - [Join Developer Discussion on a Mattermost Server for contributors](https://community.mattermost.com/signup_user_complete/?id=f1924a8db44ff3bb41c96424cdc20676)
-- [File Bugs](http://www.mattermost.org/filing-issues/)
+- [Get Help With Mattermost](https://docs.mattermost.com/guides/get-help.html)
-- [Share Feature Ideas](https://www.mattermost.org/feature-ideas/)
-- [Get Troubleshooting Help](https://forum.mattermost.org/t/how-to-use-the-troubleshooting-forum/150)
-- [Help translate Mattermost](https://handbook.mattermost.com/contributors/contributors/localization)
 
 ## Learn More