Reform request system to send out emails rather than internal requests

[yu-nix]

• Leave behind the present notification system. Rather than have request modals send a notification to users, it should format and send an email to the other user (use the HexLabs email API here).

• Adjust the request forms to take in 'message', 'email', 'subject', (ignore the headerImage). Then send a POST request to "notifications.api.hexlabs.org/emails/send."

• With the addition of memberRequests, on the email side, we will not be doing anything about that. That is, if a user requests to join multiple teams, multiple emails will be sent out, but only one of the links will be valid.

• ^^^ With that, the email should feature a link that essentially makes a POST request to add the person to the respective team. This request will use the team/join (I think) route that will handle the joining process.