feat: Implement user management service and frontend integration

- Added UserService to manage Keycloak users with license validation in the backend.
- Created API client for user management in the frontend.
- Developed user management page with functionalities to create, update, delete, and list users.
- Implemented user statistics retrieval and display.
- Added dialogs for user creation, editing, password change, and deletion confirmation.

backend/api/v1/modules/core/router.py

@@ -2,6 +2,7 @@ from .auth.routes import router as auth_router
 from .licenses.routes import router as licenses_router
 from .tenants.routes import router as tenants_router
 from .user_tenant.routes import router as user_tenant_router
+from .users.routes import router as users_router
 from .dashboard.routes import router as dashboard_router
 from fastapi import APIRouter
 
@@ -10,5 +11,6 @@ router = APIRouter()
 router.include_router(auth_router)
 router.include_router(tenants_router, prefix="/core", tags=["core / tenants"])
 router.include_router(user_tenant_router, prefix="/core", tags=["core / user-tenants"])
+router.include_router(users_router, prefix="/core", tags=["core / users"])
 router.include_router(licenses_router, prefix="/core", tags=["core / licenses"])
 router.include_router(dashboard_router, prefix="/core", tags=["core / dashboard"])