Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/build/docker/postgres.conf

@@ -0,0 +1,7 @@
+max_connections = 300
+listen_addresses = '*'
+fsync = off
+full_page_writes = off
+default_text_search_config = 'pg_catalog.english'
+commit_delay=1000
+logging_collector=off