ENH: allow to define datatypes instead of converters

Summary

Previously, converters was the only argument of the TableImporter that defined the columns that should be treated. This implied the problem that supplying colname: int would prevent the very useful parsing of NaNs done by pandas by default.

Now, there is the additional argument datatypes where columns can be supplied if no special converter function is needed (i.e. str, int, etc).

Focus

TableImporter

Test Environment

unitttest

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

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

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• 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.