[WIP] Fix ban by software version, some other under-hood changes

- Use updated version of upstream go-xmpp + fixes on client-side
- Introduce golangci-lint v2 + fixes
- Move especially noisy debugging stuff to separate config handles to be able to switch them off
- Add a bit debug to ban by software path

vendor/github.com/xmppo/go-xmpp/.travis.yml

@@ -0,0 +1,5 @@
+language: go
+go:
+  - tip
+script:
+    - go test