Add on option for users to request email addresses

[superdav42]

Users can get hosting through Ultimate Multisite but they are own their own to figure out email hosting. Ideally Ulitimate Multisite wp-admin account page would have option to create an email account. This would use cpanel api to create the mailbox for their sub domain and/or custom domain then provide the details the customer would use to access the email with webmail or IMAP or whatever. It would take special instructions similar to the custom domain special instructions because every host is different. It should integrate with many providers beyond cpanel, google business suite, microsoft exchange, titan mail, zoho mail, and proton mail are popular options.