feat: video publishing (#42)

- Prepare webrtc abstraction ( for future wasm support )
- Added track publish support for videos
  - Added LogoTrack example to simple_room demo
- Lot of cleanup
- There are compiler warnings I'll solve on our v1 release

livekit/src/proto.rs

@@ -0,0 +1,49 @@
+use crate::track;
+
+include!(concat!(env!("OUT_DIR"), "/livekit.rs"));
+
+// Conversions
+impl TryFrom<TrackType> for track::TrackKind {
+    type Error = &'static str;
+
+    fn try_from(r#type: TrackType) -> Result<Self, Self::Error> {
+        match r#type {
+            TrackType::Audio => Ok(Self::Audio),
+            TrackType::Video => Ok(Self::Video),
+            TrackType::Data => Err("data tracks are not implemented yet"),
+        }
+    }
+}
+
+impl From<track::TrackKind> for TrackType {
+    fn from(kind: track::TrackKind) -> Self {
+        match kind {
+            track::TrackKind::Audio => Self::Audio,
+            track::TrackKind::Video => Self::Video,
+        }
+    }
+}
+
+impl From<TrackSource> for track::TrackSource {
+    fn from(source: TrackSource) -> Self {
+        match source {
+            TrackSource::Camera => Self::Camera,
+            TrackSource::Microphone => Self::Microphone,
+            TrackSource::ScreenShare => Self::Screenshare,
+            TrackSource::ScreenShareAudio => Self::ScreenshareAudio,
+            TrackSource::Unknown => Self::Unknown,
+        }
+    }
+}
+
+impl From<track::TrackSource> for TrackSource {
+    fn from(source: track::TrackSource) -> Self {
+        match source {
+            track::TrackSource::Camera => Self::Camera,
+            track::TrackSource::Microphone => Self::Microphone,
+            track::TrackSource::Screenshare => Self::ScreenShare,
+            track::TrackSource::ScreenshareAudio => Self::ScreenShareAudio,
+            track::TrackSource::Unknown => Self::Unknown,
+        }
+    }
+}