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

.github/codeql/codeql-config.yml

@@ -7,8 +7,13 @@ query-filters:
         - recommendation
   - exclude:
       id: go/log-injection
+  - exclude:
+      id: js/insecure-randomness
 
 paths-ignore:
   - templates
   - tests
   - 'api4/*_local.go'
+  - webapp/channels/e2e
+  - webapp/channels/tests
+  - '**/*.test.*'