feat: allow users to pause prebuilt workspace reconciliation (#18700)

This PR provides two commands:
* `coder prebuilds pause`
* `coder prebuilds resume`

These allow the suspension of all prebuilds activity, intended for use
if prebuilds are misbehaving.

coderd/database/dump.sql

@@ -242,7 +242,8 @@ CREATE TYPE resource_type AS ENUM (
     'idp_sync_settings_group',
     'idp_sync_settings_role',
     'workspace_agent',
-    'workspace_app'
+    'workspace_app',
+    'prebuilds_settings'
 );
 
 CREATE TYPE startup_script_behavior AS ENUM (