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_unix.go

@@ -32,6 +32,8 @@ import (
 // If something fails here it means that the logging was improperly configured,
 // so we just exit with the error
 func SetupHookLogging(hooks []config.LogrusHook, componentName string) {
+	levelLogAddedMu.Lock()
+	defer levelLogAddedMu.Unlock()
 	for _, hook := range hooks {
 		// Check we received a proper logging level
 		level, err := logrus.ParseLevel(hook.Level)
@@ -85,8 +87,6 @@ func checkSyslogHookParams(params map[string]interface{}) {
 }
 
 func setupStdLogHook(level logrus.Level) {
-	levelLogAddedMu.Lock()
-	defer levelLogAddedMu.Unlock()
 	if stdLevelLogAdded[level] {
 		return
 	}