Do some mockups for Collections module

See user stories linked to NXROADMAP-165

Screens to do:

• Document view: add to collection
• Folder view: selection, add to collection. Pop up with selection list -> select a collection + creation of a new collection: titre / description.
• Browsing list of existing collection: in home (+ personal workspace) favorites + collection + shared collection (only in home)
• Share -> manage rights + (mock up share / link / user names)
• Permanent list of collection (favorites: list in the right side (floating blocks), in the footer, etc)
• Example of a collection folder actions: bulk validation, bulk publishing, zip export, pdf export, bulk download