qml: add "new (blank) profile" button to the tool bar editor dialog
Based on !5883 (merged). See the last three commits.
This dialog already has a "new profile" button, but it works by cloning the selected profile.
With this patch, "new profile" creates a blank profile (mid-button), and cloning functionality is retained in a different "clone profile" button (leftmost-button).
Request review @chub.
Edited by Fatih Uzunoğlu