algos.snapshot: Open snapshot_get_from_revision algorithm
This leverages the latest change in origin_visit_get
and
origin_visit_status_get
(paginated endpoints now) to iterate over visits and
visit statuses.
The order iterated over is from most recent to oldest to try and resolve a snapshot targetting
a specific revision.
Note: This algo got used recently in the deposit. It may serve again.
Depends on !957 (closed) Related to swh-deposit!374 (closed)
Related to T645
Test Plan
tox
Migrated from D3648 (view on Phabricator)