Removed ezcomments

> Fixes http://jira.ez.no/browse/EZP-22787
> Status: work in progress

Pretty much says it all. Not supposed to be part of the deliverables anymore.

### Todo
- [x] Remove `attribute_view_gui` calls to the comments attribute in full view templates
- [x] Remove `comments.less` + the reference in `bootstrap.less`
- [ ] regenerate CSS files