fix(embed): Checking for lightbox and embed before loading JS libs when requested through AJAX.

Refs #7107.
fix(walled_garden): ACCESS_PUBLIC no longer available in group context

When walled garden is enabled ACCESS_PUBLIC is removed from the access
options, except in the group context. This fix also removes it for the
group context.
fix(groups): removes ACCESS_PUBLIC from visibility options if walled
garden is enabled

In a walled garden site nothing is allowed to be public, this also
applies to the visibility of groups
Merge pull request #7038 from jeabakker/group-visibility-walled-garden

fix(groups): removes ACCESS_PUBLIC from visibility options if walled garden is enabled
Merge pull request #7035 from jeabakker/groups-walled-garden

fix(walled_garden): ACCESS_PUBLIC no longer available in group context
Merge pull request #7109 from brettp/embed_activity_ajax2

fix(embed): Checking for lightbox and embed before loading JS libs when ...
feature(ckeditor): add "clear formatting" button

Adds a button that can be used to reset styles e.g. after copy-pasting content from somewhere else.

Fixes #7105
Merge pull request #7129 from juho-jaakkola/ckeditor_remove_formatting

feature(ckeditor): add "clear formatting" button