Add 'remove-attr' and 'remove-class' style properties

[ameshkov]

The source for this task is here: https://github.com/AdguardTeam/Scriptlets/issues/245#issuecomment-1346110102

In addition to implementing the style properties, we should also automatically convert the uBO-style selectors. I.e. selector:remove-attr(attr) --> selector { remove-attr: attr }