tornado.IOLoop.run_sync is deprecated and must be removed from our code base.

The CLI scripts are all calling this and a replacement with asyncio.run should be possible

Caveats

• The way we handle signals needs to be adjusted
• Once asyncio.run finishes we need to ensure the tornado loop is also closed
• behaviour of preload modules may be affected if they are using loops about whether or not they are initialized before the loop is created. Preserving this behaviour is out of scope.