Incorporate spam filtering and email hiding in discourse

[robe]

I'm testing out use customize watched words ​https://discourse.osgeo.org/admin/customize/watched_words/action/block

Flagging posts as spam, as well as hiding email addresses etc. accidentally posted on forums. The email hiding is to simulate what mailman does.

To do this I had to enable watched words regular expressions

which means all watched words follow posix regex rules. So I may need to redo some of the auto tagging I had put in place before.