Enhance Discord role management by adding hoist functionality

This commit introduces a new `hoist` attribute for Discord roles, allowing team roles and the registered role to be displayed in separate groups within the Discord member list. The `RoleWorker` has been updated to ensure team roles are positioned above the registered role, improving visibility and organization. Database schema changes have been made to support the new `hoist` field, and corresponding updates have been implemented in the service layer and tests to validate the new behavior.

backend/migrations/013_discord_role_hoist.sql

@@ -0,0 +1,7 @@
+-- +mixmaker Up
+ALTER TABLE discord_managed_roles
+    ADD COLUMN hoist boolean NOT NULL DEFAULT false;
+
+-- +mixmaker Down
+ALTER TABLE discord_managed_roles
+    DROP COLUMN IF EXISTS hoist;