Headers transforms support RegEx

### What should we add or change to make your life better?
There are header transforms that allow to remove a specific header or allow specific headers. E.g. RequestHeaderRemove, ResponseHeaderRemove, ResponseHeadersAllowed etc. In cases when I need to remove or allow multiple headers with similar names it would be more convenient to use RegEx.

### Why is this important to you?
I need to remove multiple similar headers from a proxied response. E.g. "x-foo-a", "x-foo-b" etc. Now I need to list them one by one either I use ResponseHeaderRemove or ResponseHeadersAllowed.