feat: Add DNS management resources and importer

- Implemented DomainCollection, DomainDetailResource, DomainNSCollection, DomainNSResource, and DomainResource for handling DNS domain and record data.
- Created VpsServiceCollection and VpsServiceResource for VPS service management.
- Added DnsManagerNS and DnsManagerUser models to represent DNS records and user associations.
- Developed AdminZoneDnsSqlImporter for importing DNS data from SQL dumps, including customer and DNS domain records.
- Added migration scripts to update the customers table with new fields and sync foreign key references for DNS tables.
- Created a migration preview document outlining the mapping and schema changes for the admin zone DNS import.

app/Http/Requests/Domain/DomainRequest.php

@@ -17,7 +17,7 @@ class DomainRequest extends FormRequest
             'domain_name'           => 'required|string|max:255',
             'dns_manager_server_id' => 'required|integer|exists:dns_manager_servers,id',
             'user_id'               => 'nullable|array',
-            'user_id.*'             => 'integer|exists:users,id',
+            'user_id.*'             => 'integer|exists:customers,id',
         ];
     }
 }