- implement save method and let it call these tasks:
- create_web_php_fpm_pool_config if the user has no website yet
- create_file_website_hierarchy
- create_web_vhost_config
- enable_web_vhost
- implement domains.forms.relative_domain_validator
- use the validator for domain field validation in
domains.forms.CreateHostingDomainForm
- use the validator for subdomain field validation in
websites.forms.AddWebsiteForm