Bug 34587: File upload - Background job

Bug 34587: File upload - Background job

ErmSushiHarvester background job will now be initiated by either
enqueue_counter_file_processing_job or by enqueue_sushi_harvest_jobs
from Koha/ERM/UsageDataProvider.pm, the former if triggered by a manual
file upload, the latter if by the 'run now' button or by the cron script.

This commit also includes some rewording/refactoring, namely:
- COUNTER file validation now happens in the API, before enqueuing the job.
- Removal of no longer used POST /erm/counter_files endpoint
- Koha/ERM/UsageDataProvider.pm:
-- run method is now enqueue_sushi_harvest_jobs
-- new enqueue_counter_file_processing_job method
-- harvest method is now harvest_sushi
-- new set_background_job_callbacks method to set the background job callbacks
- REST/V1/ERM/UsageDataProviders
-- run method is now process_SUSHI_response
-- new process_COUNTER_file endpoint

Signed-off-by: Jessica Zairo <jzairo@bywatersolutions.com>
Signed-off-by: Michaela Sieber <michaela.sieber@kit.edu>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>