Implement kivy 2.0 and update code

[JKamlah]

Solved problems

• [x] Update the code to work with kivy 2.0.
• [x] ID assignments need to be removed.
• [x] Atm there are problems with kivymd 0.114.1 (e.g. MDTabs). New problem:
• [ ] Atm using 0.114.2dev version of kivymd while installing master branch with -> Updating to official tag 0.114.2 if released