Dcor-shared

- enh: add get_dc_instance convenience method

- tests: fix invalid make_dataset method

- fix: handle non-existent bucket when S3 object is missing
- docs: be more verbose in s3cc docstrings

- feat: implement `s3.create_presigned_upload_url` for creating presigned
upload URLs that DCOR-Aid can use to upload resources directly to S3
- feat: new S3 CKAN convenience methods submodule `s3cc`
- feat: new submodule for shared test methods `testing`
- ref: migrate ckan imports to function code so dcor_control
works on any machine
- setup: add dependency dclab 0.57.3 (boto3 resource access)

- BREAKING CHANGE: wait_for_resource now requires the resource_id
instead of the resource path
- BREAKING CHANGE: ckan installation is now mandatory
- enh: cache calls to data.wait_for_resource

- maintenance release