Skills-Search rework: query params cleanup

[RandomTannenbaum]

To make the query_params more readable, we should clean up the form field names. At the moment these looks something like this:

It's not really clear what the brackets are for, since some of them have numbers in it and some don't. Clean these up to have a uniform look and make sure the filter_params class still works.

ToDo

• [ ] The query params now have better readability
• [ ] Tests still pass and function is the same as before