Implement more spam improvements

[camfindlay]

From IRC:
you could do the rate limit based on the days since created is how many posts an hour they can make +1. So if they joined today then 0 days + 1 = 1 post an hour. If they post tomorrow then it's 1 day + 1 = 2 posts an hour. Possibly done at the IP AND account name, so if they signup for new account but still have same ip they are still limited.

replies are fine, just limit new topics perhaps

I think displaying a captcha for accounts that are less than X time old could be a good idea.

limit only new users, or simply add a "approved poster" flag which is a checkbox

[camfindlay]

@assertchris can you post the link to the rate limiting you created recently, cannot remember which module that was in ;)

[assertchris]

https://github.com/mandrew/silverstripe-quickfeedback/blob/3cf1b0356074579c2fc837a68660009de88300a4/code/extensions/QuickFeedbackExtension.php#L62-L132