Add skeleton of the proxy

mtglib/proxy_opts.go

@@ -0,0 +1,12 @@
+package mtglib
+
+type ProxyOpts struct {
+	Secret          Secret
+	Network         Network
+	AntiReplayCache AntiReplayCache
+	IPBlocklist     IPBlocklist
+	EventStream     EventStream
+	Logger          Logger
+
+	Concurrency uint
+}