Package Cluster / nutsdb:

- removing package cluster & nutsdb (+ test) in waiting stabilisation of
  dependencies
- adding olld source code in tarball file

Dependencies golang/x/exp:
- removing experiment dependency when using slices to root/slices
  package

Bump dependencies (some dependences still use exp who's need go1.22)

mail/email.go

@@ -25,7 +25,7 @@
 
 package mail
 
-import "golang.org/x/exp/slices"
+import "slices"
 
 const (
 	headerFrom       = "From"