In `media-views.js`, add `wp.media.controller.CollectionAdd` and...

In `media-views.js`, add `wp.media.controller.CollectionAdd` and `wp.media.controller.CollectionEdit` to provide an abstraction for Add and Edit screens in the media modal for collection-type things.

There are currently no instances of this. Those will be forthcoming.

See #26631.


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git-svn-id: https://core.svn.wordpress.org/trunk@27071 1a063a9b-81f0-0310-95a4-ce76da25c4cd