In the GUI, use ASGI Lifespan State, once it's supported by Hypercorn

[brianhelba]

Directly attaching things to app.state should be removed in favor of using Lifespan State, as that will ensure state is properly reset between server startups.

However, Hypercorn does not support ASGI Lifespan State yet.

These PRs are currently attempting to add such support to Hypercorn:

• implement asgi lifespan state pgjones/hypercorn#107
• Support lifespan_scope["state"] pgjones/hypercorn#110