Initial Store & Forward Implementation (#2917)

This adds store & forward relays into dendrite for p2p.
A few things have changed:
- new relay api serves new http endpoints for s&f federation
- updated outbound federation queueing which will attempt to forward
using s&f if appropriate
- database entries to track s&f relays for other nodes

internal/log.go

@@ -101,6 +101,8 @@ func SetupPprof() {
 
 // SetupStdLogging configures the logging format to standard output. Typically, it is called when the config is not yet loaded.
 func SetupStdLogging() {
+	levelLogAddedMu.Lock()
+	defer levelLogAddedMu.Unlock()
 	logrus.SetReportCaller(true)
 	logrus.SetFormatter(&utcFormatter{
 		&logrus.TextFormatter{