[Permissions] Implement getRoles (#9955)

In this PR

- introducing roles module to separate roles logic (assign a Role, get a
workspace's roles etc.) from permission logic (check if a user has a
permission)
- Introduces getRoles endpoint to fetch a workspace's roles
- introduces the first permission check: getRoles in only accessible to
users with permission on ROLE setting. Implemented
validatesUserHasWorkspaceSettingPermissionOrThrow

packages/twenty-server/src/engine/metadata-modules/permissions/permissions.exception.ts

@@ -12,4 +12,6 @@ export enum PermissionsExceptionCode {
   USER_WORKSPACE_NOT_FOUND = 'USER_WORKSPACE_NOT_FOUND',
   WORKSPACE_ID_ROLE_USER_WORKSPACE_MISMATCH = 'WORKSPACE_ID_ROLE_USER_WORKSPACE_MISMATCH',
   TOO_MANY_ADMIN_CANDIDATES = 'TOO_MANY_ADMIN_CANDIDATES',
+  USER_WORKSPACE_ALREADY_HAS_ROLE = 'USER_WORKSPACE_ALREADY_HAS_ROLE',
+  PERMISSION_DENIED = 'PERMISSION_DENIED',
 }