fix(embed): make pagination in embed colorbox usable

View mod/embed/views/default/embed/list.php is missing a base_url for navigation.

Adding 'base_url' => elgg_get_site_url() . "embed/" to the options for pagination fixes this

Refs: Issue #6357
fix(embed): Allows embedding files from the containing group

If the user is a member of the group containing the host entity, this allows
the user to embed files from that group via the lightbox.
Merge pull request #6384 from mrclay/slyhne-patch-7

Fixes pagination and group file finding in embed