lister: Unify credentials configuration structure between listers
This becomes a dictionary of key , value a dict of key , value list of dict username/password.
This allows configuration change to allow the following:
credentials:
github: # github lister
github: # has only one instance (so far)
- username: some
password: somekey
- username: one
password: onekey
- ...
gitlab: # gitlab lister
riseup: # has many instances
- username: someone
password: ...
- ...
gitlab:
- username: someone
password: ...
- ...
Related swh/infra/puppet/puppet-swh-site#1772 (closed)
Test Plan
tox
Migrated from D1518 (view on Phabricator)