Enable Sender and Receiver Reports by default

The play-from-disk examples sees the average bitrate using
Chromium 90.0.4412.3 when enabled on loopback for a 3 minute
session.

Before: 744.443
After: 3927.669

Introduced with pion/interceptor@v0.0.10

examples/save-to-disk/main.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/pion/interceptor"
 	"github.com/pion/rtcp"
 	"github.com/pion/webrtc/v3"
 	"github.com/pion/webrtc/v3/examples/internal/signal"
@@ -38,7 +39,7 @@ func main() {
 	// Everything below is the Pion WebRTC API! Thanks for using it ❤️.
 
 	// Create a MediaEngine object to configure the supported codec
-	m := webrtc.MediaEngine{}
+	m := &webrtc.MediaEngine{}
 
 	// Setup the codecs you want to use.
 	// We'll use a VP8 and Opus but you can also define your own
@@ -55,8 +56,19 @@ func main() {
 		panic(err)
 	}
 
+	// Create a InterceptorRegistry. This is the user configurable RTP/RTCP Pipeline.
+	// This provides NACKs, RTCP Reports and other features. If you use `webrtc.NewPeerConnection`
+	// this is enabled by default. If you are manually managing You MUST create a InterceptorRegistry
+	// for each PeerConnection.
+	i := &interceptor.Registry{}
+
+	// Use the default set of Interceptors
+	if err := webrtc.RegisterDefaultInterceptors(m, i); err != nil {
+		panic(err)
+	}
+
 	// Create the API object with the MediaEngine
-	api := webrtc.NewAPI(webrtc.WithMediaEngine(&m))
+	api := webrtc.NewAPI(webrtc.WithMediaEngine(m), webrtc.WithInterceptorRegistry(i))
 
 	// Prepare the configuration
 	config := webrtc.Configuration{