feat(users): add updateAdmin endpoint and enhance role assignment

- Introduced `PATCH /admin/:uuid` endpoint for admin-specific user updates.
- Updated `update` logic to handle role assignment via `rbacService`.
- Refactored `findAll` method in repository for improved readability.

backend/src/users/users.controller.ts

@@ -112,6 +112,16 @@ export class UsersController {
 		return this.usersService.remove(uuid);
 	}
 
+	@Patch("admin/:uuid")
+	@UseGuards(AuthGuard, RolesGuard)
+	@Roles("admin")
+	updateAdmin(
+		@Param("uuid") uuid: string,
+		@Body() updateUserDto: UpdateUserDto,
+	) {
+		return this.usersService.update(uuid, updateUserDto);
+	}
+
 	// Double Authentification (2FA)
 	@Post("me/2fa/setup")
 	@UseGuards(AuthGuard)