- Refactored SpamCheckService into SpamService

- Added `submitted_as_ham` to `SpamLog` to mark which logs have been submitted to Akismet.
- Added routes and controller action.

- Removed unnecessary column from `SpamLog`
- Moved creation of SpamLogs out of its own service and into SpamCheckService
- Simplified code in SpamCheckService.
- Moved move spam related code into Spammable concern

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

`render nothing: true` has been deprecated.
For more information see [pr](https://github.com/rails/rails/pull/20336)

Currently any spam detected by Akismet by non-members via API will be logged
in a separate table in the admin page.

Closes #5612