Split out a `Settings` struct from `Config`

[dongcarl]

The Settings struct is an abstract representation of frame::Settings.

Basically:

• When talking about our own connection, we should use Config.

  • e.g. in ConnectionInner's config field

• When talking about a peer's settings, we should use `Settings.

  • e.g. in SharedState's peer_config field

This separation allows us to define some conversions:

• Config -> frame::Settings

  • used in ConnectionInner::new

• &frame::Settings -> Settings

  • used in ConnectionInner::poll_control

[dongcarl]

@Ruben2424 Resolved!

[dongcarl]

Perhaps one thing to discuss is whether or not to include the Deref and DerefMut impls here: https://github.com/hyperium/h3/pull/208/files#diff-4fc440b791f25fbde8061757f9ecfdcb61af28bc20a5b3c236f0ae1f6c96db4eR181-R194

https://doc.rust-lang.org/std/ops/trait.Deref.html says that: "Deref should only be implemented for smart pointers"

[dongcarl]

@Ruben2424 Removed!