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/000017_create_roles.up.sql

@@ -0,0 +1,34 @@
+CREATE TABLE IF NOT EXISTS roles (
+    id VARCHAR(26) PRIMARY KEY,
+    name VARCHAR(64),
+    displayname VARCHAR(128),
+    description VARCHAR(1024),
+    createat bigint,
+    updateat bigint,
+    deleteat bigint,
+    permissions VARCHAR(4096),
+    schememanaged boolean,
+    UNIQUE(name)
+);
+
+ALTER TABLE roles ADD COLUMN IF NOT EXISTS builtin boolean;
+
+DO $$
+	<< migrate_if_version_below_500 >>
+DECLARE
+	current_db_version VARCHAR(100) := '';
+BEGIN
+	SELECT
+		value INTO current_db_version
+	FROM
+		systems
+	WHERE
+		name = 'Version';
+	IF (string_to_array(current_db_version, '.') < string_to_array('5.0.0', '.')) THEN
+		 UPDATE Roles SET SchemeManaged = false
+            WHERE Name NOT IN ('system_user', 'system_admin', 'team_user', 'team_admin', 'channel_user', 'channel_admin');
+	END IF;
+END migrate_if_version_below_500
+$$;
+
+ALTER TABLE roles ALTER COLUMN permissions TYPE TEXT;