feat(coderd): add tasks rbac object (#20234)

This change adds RBAC for tasks.

Updates coder/internal#948
Supersedes coder/coder#20212

coderd/database/dump.sql

@@ -197,7 +197,12 @@ CREATE TYPE api_key_scope AS ENUM (
     'workspace_agent_devcontainers:*',
     'workspace_agent_resource_monitor:*',
     'workspace_dormant:*',
-    'workspace_proxy:*'
+    'workspace_proxy:*',
+    'task:create',
+    'task:read',
+    'task:update',
+    'task:delete',
+    'task:*'
 );
 
 CREATE TYPE app_sharing_level AS ENUM (