Use capacitor (completely remove cordova)

What needs to be changed?

Cordova (and cordova plugins if possible) need to be replaced.

How is the current state not sufficient?

Some cordova plugins are outdated, e.g. [calendar plugin](https://github.com/EddyVerbruggen/Calendar-PhoneGap-Plugin with which we had a lot of problems because of bugs that are not patched.

Edit: for the calendar, at this time there is no capacitor alternative.

More info.

Which changes are necessary?

Switch to capacitor.

Do the proposed changes impact current use cases?

Cordova imports and code need to be replaced with imports and syntax used for capacitor.