[Filter Input] Clear value (and focus)

[atomworks]

At the moment we don't have a button to clear the value of the field itself, you have to delete manually or use the one in the filter conditions list. We should add a button to clear this and then focus the field (as we assume the intent could next be to replace the value).

This become a little trickier as we have a close button that we use here for those optional filter inputs that we add. For this, it's better to use a backspace style icon to clear the value. For items that can be closed, perhaps the first click clears it and then we show the X to close.