2811 preserve params on clearfilter

#2811 Clear Filters button should preserve custom query params
Introduce `clear_filters` action in controller, send request to it with current location (through ajax request), process it and return with the correct URL, and then set it to window.location. With that change it will be possible to customize keys that should be removed.

Also, current implementation of the filters isn't perfect. In one of my applications I'm saving the filter parameters as long as users browsing in the resource. It's very helpful, when user are editing the models, and then returning to the index. In normal AA implementation, you will be redirected to the index without pagination, scopes and queries parameters, and that's really annoying for the admins to use AA, because you have to choose scope, page and filters again and again, right after you edit just one resource.

As the temporary solution, this PR is good. It fixes at least some issues, but it's not maintainable and moves AA to the wrong direction (but it's just my opinion).