Upload Overdrive

[peterjan]

I discovered our cancelled out overdrives essentially make an uploader unusable for all other sectors. I refactored in a couple of steps and the more I changed the more it made sense to essentially extend sectorCtx with not just its ctx and cancel func but everything related to the sector.

[ChrisSchinnerl]

 === RUN   TestUploadDownloadSpending
  2023-12-07T16:47:47Z	ERROR	autopilot.migrator	autopilot/migrator.go:158	worker: migration 1/3 failed, key: key:baf2a3a18250a0b825bec2c8d2f7218208333f8005d88b7d2d119ae39b1c9dd7, health: 0, overpaid: false, err: failed to migrate slab; failed to upload slab for migration: 0 < 1: not enough contracts to support requested redundancy
  2023-12-07T16:47:47Z	ERROR	worker.worker	worker/worker.go:1137	couldn't upload object: no candidate uploader found
      cluster_test.go:879: couldn't upload object: no candidate uploader found

Seems like tests are failing due to this

[ChrisSchinnerl]

Lgtm but this one test keeps failing for some reason