Fix Email Regex to not match on extra characters

[Tankanow]

Change email regex match to fullmatch

This PR is about the current method used to conditionally match user and domain regex to email.
currently, it's using match which wrongfully accepts entries if domain has special characters after .com

it currently accepts, john@voluptuous.com> or john!@voluptuous.org!@($*!

thus, we need to fullmatch the domain or user to avoid such entries and validate them properly.

[Tankanow]

I created this issue just for bookkeeping with the latest commit already on master: e5e3b51.