Allow a study to specify a schema

[dogversioning]

This PR makes the following changes:

• Allows a study to specify an explict schema
  • Auto transforms table names if this is done - so 'study__table' becomes just 'table', so reverting this is a config-only change
• adds tests for --continue and --builder CLI args, fixing one bug with the former.

Checklist

• [X] Consider if documentation (like in docs/) needs to be updated
• [X] Consider if tests should be added
• [] Update template repo if there are changes to study configuration

[github-actions[bot]]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
1906	1828	96%	90%	🟢

New Files

No new covered files...

Modified Files

File	Coverage	Status
cumulus_library/actions/builder.py	96%	🟢
cumulus_library/actions/cleaner.py	97%	🟢
cumulus_library/actions/exporter.py	97%	🟢
cumulus_library/base_table_builder.py	97%	🟢
cumulus_library/base_utils.py	97%	🟢
cumulus_library/cli.py	97%	🟢
cumulus_library/databases.py	96%	🟢
cumulus_library/protected_table_builder.py	100%	🟢
cumulus_library/study_parser.py	100%	🟢
TOTAL	97%	🟢

updated for commit: 8195b66 by action🐍