Make the canvas input configurable

This adds a page to the preferences dialog that allows you to select a
profile and configure the input for that profile.

BUG: 298714
BUG: 298462
BUG: 302478
BUG: 317201
FIXED-IN: 2.8
REVIEW: 111391
GUI: Added a new "Canvas Input Settings" page.
DIGEST: Krita's canva input is now configurable.