Clients of LaunchServer can now provide a list of allowed handlers,
optionally with a specific set of URLs. The list can be sealed to
prevent future additions to it.
If LaunchServer receives a request to open something not on the allowed
handlers list, it will disconnect the client immediately.
The main idea here is to allow otherwise restricted programs to launch
specific things, e.g "Help" to open their manual, or "Browser" to load
the SerenityOS home page. :^)
By adding a special LauncherType::Application we can still
get meta data for the application, but also know that we should
consider executing that binary as the default action. LaunchServer
will not do this for us, as it should probably not be allowed to
run arbitrary binaries that haven't been registered as handlers.
Adds metadata about apps for what file types and protocols they can
handle, then consumes that in the LaunchServer. The LaunchServer can
then use that to offer multiple options for what apps can open a given
URL. Callers can then pass back the handler name to the LaunchServer to
use an alternate app :)
Moves DirectoryServices out of LibCore (because we need to link with
LibIPC), renames it Desktop::Launcher (because Desktop::DesktopServices
doesn't scan right) and ports it to use the LaunchServer which is now
responsible for starting programs for a file.
