cran loader: Add implementation
which means:
- add loader implementation with cli auto-registration (
swh loader cran -h
) - add task implementation with scheduler task auto-registration (task-type
load-cran
) - tested
Note: The diff is annoyingly a tad big because i extracted common behavior functions in package.utils modules...
Related T2026
Test Plan
tox
Migrated from D2463 (view on Phabricator)