Merge branch 'f-select-subproperties' into 'dev'

f-select-subproperties -> dev

# Summary

See summary of https://gitlab.com/caosdb/caosdb-webui/-/merge_requests/72

# Focus

This MR mainly contains a convenience function for converting results of SELECT Queries into a table (too be precise, a list of tuples, which is particularly convenient for using `pandas.DataFrame`). It was added to write maintainable tests in the pyinttest repo for SELECT queries.

# Test Environment

See setup in https://gitlab.com/caosdb/caosdb-webui/-/merge_requests/72 and test with pylib instead.

# Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a
focus and create gitlab comments for the reviewer. They should guide the
reviewer through the changes, explain your changes and also point out open
questions. For further good practices have a look at [our review
guidelines](https://gitlab.com/caosdb/caosdb/-/blob/dev/REVIEW_GUIDELINES.md)

- [x] All automated tests pass
- [x] Reference related Issues
- [x] Up-to-date CHANGELOG.md
- [x] Annotations in code (Gitlab comments)
  - Intent of new code
  - Problems with old code
  - Why this implementation?


# Check List for the Reviewer


- [x] I understand the intent of this MR
- [ ] All automated tests pass
- [x] Up-to-date CHANGELOG.md
- [x] The test environment setup works and the intended behavior is
  reproducible in the test environment
- [x] In-code documentation and comments are up-to-date.
- [ ] Check: Are there spezifications? Are they satisfied?

For further good practices have a look at [our review guidelines](https://gitlab.com/caosdb/caosdb/-/blob/dev/REVIEW_GUIDELINES.md).

See merge request caosdb/caosdb-pylib!31