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/channels/db/migrations/postgres/000001_create_teams.down.sql

@@ -0,0 +1,14 @@
+CREATE INDEX IF NOT EXISTS idx_teams_name ON teams (name);
+
+ALTER TABLE teams DROP COLUMN IF EXISTS allowopeninvite;
+ALTER TABLE teams DROP COLUMN IF EXISTS lastteamiconupdate;
+ALTER TABLE teams DROP COLUMN IF EXISTS description;
+ALTER TABLE teams DROP COLUMN IF EXISTS groupconstrained;
+
+DROP INDEX IF EXISTS idx_teams_invite_id;
+DROP INDEX IF EXISTS idx_teams_update_at;
+DROP INDEX IF EXISTS idx_teams_create_at;
+DROP INDEX IF EXISTS idx_teams_delete_at;
+DROP INDEX IF EXISTS idx_teams_scheme_id;
+
+DROP TABLE IF EXISTS teams;