Extract contacts libraries to another project and use it

[alagane]

In order to remove dependency links between SPAs, contacts libraries should be extracted to a new project and used as a dependency for SPAs needing them.

The new project will be named esn-frontend-contacts-libs.
It will be "forked" (cannot literally fork it with GitHub on the same organisation, only one fork permitted AND no issue can be created on fork) from this project, so the git file history of the libraries files can still be viewed easily.

Tasks

• Create a branch for the libraries, without the SPA files.
• Merge it on esn-frontend-contacts-libs
• Use esn-frontend-contacts-libs instead of esn-frontend-contacts for esn-frontend-admin
• Create a branch where the SPA uses esn-frontend-contacts-libs dependency, and the libraries code is removed
• Merge it on esn-frontend-contacts
• Clean unneeded code and dependencies on each project after the extraction