MM-41988 Updated links to legacy domain about.mm.com (#19552)

* Updated links to legacy domain about.mm.com

* Legacy link updates

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* about.mm.com URL updates

* mattermost.org URL updates

* forum.mm.org URL update

* Update .github/ISSUE_TEMPLATE.md

* Update .github/ISSUE_TEMPLATE.md

* Un-deleted language files

* Update README.md

* Update tests/test-config.json

* fix some test due to url updating (#19787)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>
Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>

.github/ISSUE_TEMPLATE.md

@@ -1,12 +1,12 @@
-Per Mattermost guidelines, GitHub issues are for bug reports: <http://www.mattermost.org/filing-issues/>.
+Per Mattermost guidelines, GitHub issues are for bug reports: <https://handbook.mattermost.com/contributors/contributors/ways-to-contribute/>.
 
-For troubleshooting see: http://forum.mattermost.org/.
-For feature proposals see: http://www.mattermost.org/feature-requests/
+For troubleshooting see: https://forum.mattermost.com/.
+For feature proposals see: https://www.mattermost.com/feature-ideas/
 
 If you've found a bug--something appears unintentional--please follow these steps:
 
 1. Confirm you’re filing a new issue. [Search existing tickets in Jira](https://mattermost.atlassian.net/jira/software/c/projects/MM/issues/) to ensure that the ticket does not already exist.
-2. Confirm your issue does not involve security. Otherwise, please see our [Responsible Disclosure Policy](https://about.mattermost.com/report-security-issue/).
+2. Confirm your issue does not involve security. Otherwise, please see our [Responsible Disclosure Policy](https://mattermost.com/security-vulnerability-report/).
 3. [File a new issue](https://github.com/mattermost/mattermost-server/issues/new) using the format below. Mattermost will confirm steps to reproduce and file in Jira, or ask for more details if there is trouble reproducing it. If there's already an existing bug in Jira, it will be linked back to the GitHub issue so you can track when it gets fixed. 
 
 #### Summary