Update spam prevention

closes #3468
- added rate limit to deny more than 5 attempt every hour
- updated spam prevention to be configurable
- added config values spamTimeout, ratePeriode, rateAttempts
- added ratePeriode:1 to config.example.js to prevent functional tests
from hitting the rate limit
- added spamTimeout:5 to config.example.js since I didn't hit the spam prevention randomly