[#70761980] Add comment notification mails

Add a comment mailer
Add a layout for comment mails
Add a notification for comments on event and replies to comments.
[#70761980] Method to send emails from comment c
Merge branch 'master' into comment_emails
[#70761980] Refactor comment mailer and add specs
[#70761980] Comment mailer tweak

Add comment url
Add quotes around comment
[#70761980] Check user preference before sending

Check for user preference to ignore all comment notifications before
sending.
[#70761980] Event spec datetime fix
[#70761980] Add link to user account
[#70761980] Add test for ignoring comments
Merge branch 'master' into comment_emails