feat(webp): add WebP streaming and snapshot APIs

- implement WebP streaming with multipart support
- add snapshot endpoint for WebP format with quality options
- introduce WebP encoding using pure Go library without FFmpeg
- update documentation and links for new WebP features

pkg/webp/rtp.go

@@ -0,0 +1,11 @@
+package webp
+
+import (
+	"github.com/AlexxIT/go2rtc/pkg/core"
+	"github.com/AlexxIT/go2rtc/pkg/mjpeg"
+)
+
+// RTPDepay depayloads RTP/JPEG packets and converts the resulting JPEG frame to WebP.
+func RTPDepay(handler core.HandlerFunc) core.HandlerFunc {
+	return mjpeg.RTPDepay(JPEGToWebP(handler))
+}