feat!: new quic-rpc, simlified generics, bump MSRV to 1.76 (#2268)

## Description

Adapts iroh for n0-computer/quic-rpc#76

Wit this change, a quic client is
`pub type QuicIroh = Iroh<QuinnConnection<RpcService>>`
instead of
`pub type QuicIroh = Iroh<QuinnConnection<ProviderRequest,
ProviderResponse>>`

## Breaking Changes
* Increased mimimal supported rust version (MSRV) from 1.75 to 1.76
* The generics of the iroh clients changed: Instead of taking
`ProviderRequest, ProviderResponse` as generics, they now take
`RpcService`

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->

## Change checklist

- [x] Self-review.
- [x] Documentation updates if relevant.
- [x] Tests if relevant.
- [x] All breaking changes documented.

---------

Co-authored-by: dignifiedquire <[email protected]>

Cargo.toml

@@ -9,7 +9,7 @@ authors = ["n0 team"]
 repository = "https://github.com/n0-computer/iroh"
 
 # Sadly this also needs to be updated in .github/workflows/ci.yml
-rust-version = "1.75"
+rust-version = "1.76"
 
 [lints]
 workspace = true