This removes the old autoplay allowlist file in favor of the new site
setting. We still support the command-line flag to enable autoplay
globally, as this is needed for WPT.
This brings keyboard shortcuts for the inspector up with common
convention in FF and Chrome: Ctrl+Shift+C now also opens the inspector,
and F12, Ctrl+W, and Ctrl+Shift+I now close the inspector when the
inspector window is focused.
Resolves#972
m_hover_label did not have checks if the mouse is in the same location.
This caused clickable URLs to be hidden.
Also shortened the label text to not be longer than half of the window.
