[jobs-cli] move jobs load to backend
- minor refactor to accomodate the jobs load feature
- move jobs load feature to backend
Depends-on: !45 (merged)
Depends-on: toolforge-weld!49 (merged)
Depends-on: toolforge-weld!50 (merged)
Bug: T366209
Signed-off-by: Ndibe Raymond Olisaemeka rolisaemeka-ctr@wikimedia.org