Add /provenance/whereis/ Web API endpoint wrapping call to whereis
operation from swh-provenance API. It enables to get a qualified SWHID
with provenance info from a core SWHID.

Add /provenance/whereare/ Web API endpoint wrapping call to whereare
operation from swh-provenance API. It enables to get qualified SWHIDs
with provenance info from a list of core SWHIDs.

These endpoints are protected by authentication and a user permission
named "swh.web.api.provenance".

Related to swh/infra/sysadm-environment#5397.