Allow passing in TLS configuration

[ConradIrwin]

This change makes it possible for users of the library to pass their own TLS

It also bumps to the latest tokio-tungstenite so that the version of rustls in
use matches what we are using at Zed.

We've been through a number of different possible rustls connectors, and we're
currently using one (rustls-platform-verifier) that doesn't have feature flags
in livekit or tungstenite yet.

Instead of requiring that every transitive dependency supports the rustls feature flags we need,
it's much easier to pass only the __rustls-tls feature flag and pass the Connector
that we create with our configuration down the stack.

The main disadvantage of this approach is that if you use the __rustls-tls
flag, and don't pass a Connector, you get a panic when connecting to a wss://
URL.

[ilo-nanpa]

it seems like you haven't added any nanpa changeset files to this PR.

if this pull request includes changes to code, make sure to add a changeset, by writing a file to .nanpa/<unique-name>.kdl:

minor type="added" "Introduce frobnication algorithm"

refer to the manpage for more information.

[Be-ing]

Conflicting changes have been merged since this was opened. I rebased it on the current main branch in #755.

[davidzhao]

Thanks @Be-ing! closing this one in favor of #755