Use LiveKit's Rust SDK on Linux while continue using Swift SDK on Mac (#21550)

Similar to #20826 but keeps the Swift implementation. There were quite a
few changes in the `call` crate, and so that code now has two variants.

Closes #13714

Release Notes:

- Added preliminary Linux support for voice chat and viewing
screenshares.

---------

Co-authored-by: Kirill Bulatov <mail4score@gmail.com>
Co-authored-by: Kirill Bulatov <kirill@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>

crates/livekit_client/Cargo.toml

@@ -0,0 +1,65 @@
+[package]
+name = "livekit_client"
+version = "0.1.0"
+edition = "2021"
+description = "Logic for using LiveKit with GPUI"
+publish = false
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/livekit_client.rs"
+doctest = false
+
+[[example]]
+name = "test_app"
+
+[features]
+no-webrtc = []
+test-support = [
+    "collections/test-support",
+    "gpui/test-support",
+    "nanoid",
+]
+
+[dependencies]
+anyhow.workspace = true
+async-trait.workspace = true
+collections.workspace = true
+cpal = "0.15"
+futures.workspace = true
+gpui.workspace = true
+http_2 = { package = "http", version = "0.2.1" }
+livekit_server.workspace = true
+log.workspace = true
+media.workspace = true
+nanoid = { workspace = true, optional = true}
+parking_lot.workspace = true
+postage.workspace = true
+util.workspace = true
+http_client.workspace = true
+smallvec.workspace = true
+image.workspace = true
+
+[target.'cfg(not(target_os = "windows"))'.dependencies]
+livekit.workspace = true
+
+[target.'cfg(target_os = "macos")'.dependencies]
+core-foundation.workspace = true
+coreaudio-rs = "0.12.1"
+
+[dev-dependencies]
+collections = { workspace = true, features = ["test-support"] }
+gpui = { workspace = true, features = ["test-support"] }
+nanoid.workspace = true
+sha2.workspace = true
+simplelog.workspace = true
+
+[build-dependencies]
+serde.workspace = true
+serde_json.workspace = true
+
+[package.metadata.cargo-machete]
+ignored = ["serde_json"]