Rework reader

[ludwiglierhammer]

This PR is related to #334

modules to rework

• converters
• decoders
• validators
• reader
• filereader

tasks

• disentangle Configurator, FileReader and MDFFileReader
• update and add docstrings
• add unit test
• update tests for mdf_reader.reader
• update tests for mdf_reader.writer
• update CHANGELOG
• update documentation -> see Update documentation #347

[github-actions]

Warning
This Pull Request is coming from a fork and must be manually tagged approved
in order to perform additional testing.

[ludwiglierhammer]

Hi @JanWillruth, from my side this PR is ready to merge. Please review my changes.

[ludwiglierhammer]

Hi @jtsiddons, in this PR I attempted to untangle the mdf_reader module, make it more readable and modular, and added some unit tests. Feel free to have a look at my changes. I am looking forward to your comments/suggestions. We are in no hurry, so take your time. Hopefully, you will find some time for it.

[ludwiglierhammer]

Hi @jtsiddons, I'll merge this PR. Please contact me or create any new issues if you have any further suggestions or comments.

[jtsiddons]

Thanks for the changes @ludwiglierhammer. Sorry I've not had chance to look through them yet. I'll update my copies and let you know I have any issues with it.