feat: Introduce client management and integration updates

- Added client_id field to StoreTenantRequest and UpdateTenantRequest for tenant management.
- Updated TenantResource to include client_id in the response.
- Created migration to establish clients table and link tenants to clients.
- Migrated existing tenant integrations to client_integrations table.
- Grouped specific tenants under a shared client (OnTicket) in a new migration.
- Updated seeders to reflect new client structure and relationships.
- Adjusted integration configurations to require client instead of tenant.
- Added tests for client integration functionality and ensured existing tests reflect the new client structure.

database/seeders/EmailIntegrationSeeder.php

@@ -17,7 +17,7 @@ class EmailIntegrationSeeder extends Seeder
             [
                 'name' => 'Email',
                 'url' => null,
-                'requires_tenant_configuration' => false,
+                'requires_client_configuration' => false,
                 'integration_data_schema' => [
                     'MAIL_MAILER' => 'required|string|in:smtp',
                     'MAIL_SCHEME' => 'required|string|in:smtp',