Ckanext-dcor-depot

- BREANKING: remove `depotize` and `internal` submodules and functionalities
- feat: introduce job for backing up data from S3 to local block storage
- ref: migrate to dcor_shared 0.8.0
- ref: use f-strings
- ref: upload figshare depot data directly to S3
- ref: move methods from `depot` submodule to `util`
- ref: append `_job` to background job method names

- maintenance release

- enh: add --verify-checksum flag to dcor-migrate-resources-to-object_store
- setup: bump dcor_shared to 0.5.5
- setup: bump dclab to 0.56.2

- enh: upload previews to S3 with dcor-migrate-resources-to-object_store

- enh: pass --verify-existence to dcor-migrate-resources-to-object_store
- setup: bump dcor_shared to 0.5.3

- enh: support invalid datasets when uploading to S3