[FIX] website_forum links which should not be, post-install crawler

* move URLs of purely-JS-hook <a> to data-href so the crawler does not try to
  access them (they're JSON-RPC endpoints...)
* replace side-effecting links (...) by styled buttons
* fix crawler to not take fragments in account when deduplicating and
  navigating URLs
[FIX] website_crm, website_event_sale: remove stray prints

also do some trivial cleanup/simplification of website_crm while at it:

* Initialize a dict directly via literal
* Use straightforward dict copy instead of whatever that convoluted crap was
* Use gencomp for set creation
* Lift a pair of keysets to the original dict creation
[IMP] email_template simplified form view: add link to website
[IMP] website_event_track: simplify event_agenda
[FIX] various website modules, re-enable crawler tests

* fix crawler to discard URL fragments before deduplicating and crawling
* fix website_forum links which should not be links (either because their urls
  are JSON-RPC methods or because their urls are side-effecting
* remove stray print statements
* side-improvements (simplifications) to some methods