Improve server fn urls for debugging, telemetry

[willhoney7]

It's pretty painful that the server functions are completely obfuscated for a few reasons.

1. When debugging/looking at the network tab. You have to dig into each one and if you dig in, you might be able to tell which server function it is calling.
2. For telemetry reasons in sentry/similar. I'd like to look at which server functions are slow (by looking at http request data) and if they're all keyed by an obfuscated hash, I can't easily determine which server function it is.

I would like to suggest having the function name as a part of the server fn urls. Something like:
/_serverFn/create_user_ey32343433. It could snake case the names, etc.. I don't think the file path or name should be in the URL.

I think this should happen in dev mode by default for sure, and I would also suggest production as well.