Submit to Akismet Part 1 (Issues)

What does this MR do?

This MR will allow us to submit spam (or ham) issues to Akismet to train the filter.

Tasks

• Add information to the database about the user (IP Address, User Agent) and make it reusable
• Save user information on issue creation
• Add methods to submit information to Akismet
• It should be easy to make any model a Spammable one
• Allow admins to submit false positives as ham (Submit SpamLog as ham)
• Allow admins to submit false negatives as spam (Submit Issue as spam)
• Make sure everything is tested
• Add documentation

What are the relevant issue numbers?

Related to #5932 (closed) #5573 (moved) gitlab-com/infrastructure#14

Screenshots (if relevant)

Spam Logs:

(sorry about the username, Akismet needs the user to be viagra in order to always mark it as spam for tests).

Issues:

/cc @MrChrisW @DouweM