browse: Better promote citation interface
- Instead of using a popover displayable through the 'Show identifiers' entry in the 'Actions' menu, prefer to use a panel sliding from the right of the browse views displayable by clicking on a tab handle 'How to cite ?' always visible when the user scroll the views.
- Activate optional identifier parts by default
- For content identifier, synchronize the lines optional part with the selection performed by the user
Closes T1092