This is the same behavior as RequestServer, with the added benefit that
we know how to gracefully reconnect ImageDecoder to all WebContent
processes on restart.
This makes WebView::Database wrap around sqlite3 instead of LibSQL. The
effect on outside callers is pretty minimal. The main consequences are:
1. We must ensure the Cookie table exists before preparing any SQL
statements involving that table.
2. We can use an INSERT OR REPLACE statement instead of separate INSERT
and UPDATE statements.
It previously resided in LibWebView to hide the details of launching a
singleton process. That functionality now lives in LibCore. By moving
this to Ladybird, we will be able to register the process with the task
manager.
