Add the ability to return a deep view of reference-repository

This allow to get a deep view of the reference api by passing the
`deep` GET parameters to the request. It is also possible to request a
single site or the specific list of nodes assigned to an OAR job id.
3 jobs for features/#12051_v2 in 21 minutes and 47 seconds (queued for 1 second)
Status Name Job ID Coverage
  Lint
passed rubocop #742757
grid5000-docker

00:01:35

 
  Test
passed test-for-buster #742758
grid5000-docker

00:09:10

85.84%
 
  Deb
passed deb-for-buster #742759
grid5000-docker

00:11:01