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.
LibWebView now knows how to launch RequestServer and ImageDecoderServer
without help from the UI, so let's move ownership of these services over
to LibWebView for de-duplication.
We will want to re-inform WebContent of the system visibility state when
we create a new process after a crash. This changes the IPC to just send
the enum value directly, instead of a boolean, so that we can just store
that enum value directly on the ViewImplementation class.
