Unify dialog interaction by removing the apply and cancel buttons

[thinkh]

At the moment the interaction of the dialogs differ a lot from each other. For instance, the change visualization dialog applies changes immediately, where as the mapping dialog applies a preview immediately, but the user has to choose between cancel, reset and apply. That is confusing and should be unified.

I suggest that we remove the apply and cancel button and apply the changes in all dialogs immediately. Only for some complex dialogs (e.g. the mapping dialog a reset button) is helpful to restore the initial state.

[sgratzl]

some operations are expensive. including filtering and searching. So applying everything immediately when the user enters something can be costly.

[mstreit]

but that does not change the fact that it is inconsistent at the moment. for instance, we already apply costly transformations (e.g., invert) immediately (sometimes even although there is a apply button). my feeling is that we should always apply actions immediately - even if it takes some time (it's usually below 1s though).

[thinkh]

In addition to @mstreit comment: We can also show a spinner/loading icon while the change is applied.