Progress in milestone 2

Have a very basic UI

client_node/build.rs

@@ -0,0 +1,5 @@
+fn main() {
+    // Force linking of additional abseil libraries that webrtc-audio-processing-sys
+    // might miss depending on the system's abseil version.
+    println!("cargo:rustc-link-lib=absl_strings_internal");
+}