[wip][ENG-9706] migrate_osfmetrics_6to8

[aaxelb]

Ticket

• ENG-9706

Purpose

migrate osf-metrics data from elasticsearch6 to elasticsearch8

Changes

• add management command migrate_osfmetrics_6to8 that:
  • (unless --no-counts) displays counts of documents in osf-metrics indexes in both elastic6 and elastic8
  • (if --start) schedules tasks to copy osf-metrics data from elastic6 to elastic8 (making slight changes along the way)
• add/use background_migration task queue, as another way to check progress
• update djelme dependency (parallel [ENG-9706] support osfmetrics migration django-elasticsearch-metrics#96 )
• add Elastic6To8State index in es8 to store when the migration was started
• tidy/improve djelme recordtypes in osf.metrics.es8_metrics
  • loosen some validation to fit actual usage
  • omit "es8" from es8 index names
  • set a lower timeseries_index_timedepth for reports (e.g. once-a-day or once-a-month reports would be fine in yearly indexes)

for any testing locally, if you haven't been using your local osf, might want to run management commands to get fake data: fake_metrics_reports, make_dummy_pageviews_for_metrics, populate_impact_preprint_metrics, ...

Side Effects

QE Notes

CE Notes

Documentation