Fixes #3169 Hide Tracking icon for file URIs

[keianhzo]

Fixes #3169 This PR refactors the URL buttons (etp, popups, webxr, drm) and icons (loading, ssl) visibility rules to the view model as it has grown quite a lot and makes the XML very crowded and hard to read.

Also adds a number of fixes:

• Hides the ETP icon for file URIs
• Hides the URL buttons if the URL bar is focused
• Shows the file name in the title bar for file URIs (instead of just file://)