[FIX] website_forum: restore bind to onclick because CKE Editor uses it, so on('click', fun) breaks things.

Fixes bugs with z-index error on some popups (image selector for example...)
[FIX] website_forum: fix error 500 when editing an answer

Was caused by missing tags.
Also fix also backwards-compatibility for textext selection method.
[FIX] website_forum: use other attr than value to init select2

The backend would otherwise fail because the value has been already processed