remove direct acces to col's config and other less important stuff

[Arthur-Milchior]

Description

Remove direct access to config, so that there is no more error message from latest anki.

Remove all 2.0 code; I believe I remember you're not updating it anymore.

Ensure that I can clone git directly in addon folder and still use the add-on

Each feature in a separate commit, so that you can take only the one you carea bout

Checklist:

Please replace the space inside the brackets with an x and fill out the ellipses if the following items apply:

• [x] I've read and understood the contribution guidelines
• [x] I've tested my changes against at least one of the following Anki builds:
  • [x] Latest standard Anki 2.1 binary build [required for Anki-compatible 2.1 add-ons]
  • [ ] Latest alternative Anki 2.1 binary build
  • [ ] Latest Anki 2.0 binary build [required for Anki 2.0-compatible add-ons]
• [x] I've tested my changes on at least one of the following platforms:
  • [x] Linux, version:
  • [ ] Windows, version:
  • [ ] macOS, version:
• [ ] My changes potentially affect non-desktop platforms, of which I've tested:
  • [ ] AnkiMobile, version:
  • [ ] AnkiDroid, version:
  • [ ] AnkiWeb