Revert "Restore spam prevention"
Merge pull request #3307 from TryGhost/revert-3282-issue#3128

Revert "Restore spam prevention"
New signup screen

See #3082 - This borrows setup screen styles for now
Fade in the setup form
Merge pull request #3306 from JohnONolan/fadeinsetup

Fade in the setup form
Merge pull request #3308 from JohnONolan/newsignup

New signup screen
Restored spam prevention

closes #3128
- added spam prevention middleware
- restored tests
Fix tests failing because of spam protection

closes #3128 (now really)
- added express variable disableLoginLimiter
- added disableLoginLimiter to all tests that use Ghost as module and
do authentication
- fixed isSetup not working for status other than active
- removed ‚Ensure a User is Registered‘ test as this is covered by the
new setup test