flexform config for all plugins

Integrate a general function into the AbstractController to
handle offset calculation for the pagination.

Alterring GET parameters should never be done. Instead using method
parameters to alter functionality.
This fixes side effects on the canonical URL generation, if the news
plugin is present with one of the list-Actions assigned.

- TCA tags field fix
- Module buttons/links updated
- New Module icons
- Added tags to list items
- News Module link in Page Module
- Labels updated
- Selected Language header
- pages_language_overlay author default value
- Module documentation

- Alternative page links (if no category page selected)
- BE listing with filters
- Multilanguage feature
- Edit page content link
- User restrictions respected
- Licensing service
- News/Category records creation links