Enhance user plan management and update related endpoints

- Added new configuration options for user plans in `.env.example`, including `Plans__MaxCustomConfigCount` and `Plans__MinCustomConfigCount`.
- Introduced `MapPlanEndpoints` in `Program.cs` to handle plan-related API routes.
- Implemented `SetUserPlan` endpoint in `RoleEndpoints` to allow admins to assign plans to users.
- Removed deprecated role request approval endpoints from `AdminSupportEndpoints`.
- Updated `ITelegramNotifier` and related classes to reflect changes in role request handling and payment notifications.
- Refactored role management commands to remove `MaxConfigs` and focus on `MaxIpLimit` and billing settings.
- Enhanced billing request handling to accommodate plan changes instead of role changes.
- Updated various interfaces and command handlers to support new plan management features.

backend/tests/PnvPanel.Application.Tests/Admin/Maintenance/FactoryResetCommandHandlerTests.cs

@@ -72,8 +72,8 @@ public class FactoryResetCommandHandlerTests
             .Returns(
                 new List<RoleDto>
                 {
-                    new(adminRoleId, "admin", -1, -1, IsSystem: true, BillingEnabled: false),
-                    new(customRoleId, "premium", 10, 5, IsSystem: false, BillingEnabled: false),
+                    new(adminRoleId, "admin", -1, IsSystem: true, BillingEnabled: false),
+                    new(customRoleId, "premium", 5, IsSystem: false, BillingEnabled: false),
                 }
             );
         _roleService