✨ Add SAPBW source and Prefect tasks

[gwieloch]

Summary

SAP BW connector migration from viadot 1 to viadot 2. Also added some utility functions into viadot utils.

Importance

Required by the migration project.

Checklist

This PR:

• follows the guidelines laid out in CONTRIBUTING.md
• links relevant issue(s)
• adds/updates tests (if appropriate)
• adds/updates docstrings (if appropriate)
• adds an entry in CHANGELOG.md

[trymzet]

@gwieloch it seems the checks are failing, can you make sure they pass first, then request PR review? Otherwise I would need to check the same code twice.

Also, pls rebase as well.

As for the tests failing due to pyrfc not being installed, you need to escape this import in the source, tasks, and tests, same as in the SAP RFC source:
https://github.com/dyvenia/viadot/blob/2.0/src/viadot/sources/sap_rfc.py#L19-L24
https://github.com/dyvenia/viadot/blob/2.0/tests/unit/test_sap_rfc.py#L6-L9
https://github.com/dyvenia/viadot/blob/2.0/src/viadot/orchestration/prefect/tasks/sap_rfc.py#L11-L12

For more info, see the "optional dependencies" sections in the developer guide docs https://viadot.docs.dyvenia.com/developer_guide/

[trymzet]

Checks not passing

[trymzet]

Added my comments. Some unit tests should also be added.