[FEATURE] Validate email addresses

[danry25]

What is the problem that this feature solves? Sometimes clients submit orders with invalid email addresses like name@domain without a TLD.

Describe the solution you'd like Validate that there is some text before and after the @ and the domain used resolves to a valid MX record.

How will this improve revenue or reduce our costs? This will filter out the obviously invalid email addresses, making it more likely that we have a valid contact email address on file.

[uncheckederror]

We now check the MX record for the domain provided for an email address and return the above message, if no MX record is found.

[uncheckederror]

@danry25 give it a shot with a domain that you know has no MX record and then a valid email address to verify that this works now.