feat(p2p): file transfer p2p feature

src/background/magnetParse.js

@@ -0,0 +1,8 @@
+module.exports = (magnet) => {
+	const match = /magnet:\?xt=urn:btih:([0-9a-f]+)/i.exec(magnet)
+	if(!match)
+		return
+	if(match[1].length === 40)
+		return match[1].toLowerCase()
+	return
+}