* fix links to samples
* remove activator links to fsm-sample
* we are reducing the number of samples to maintain and since samples
are mostly interesting for new users most of them will be based on
Akka Typed
* adding Example project section at the end of corresponding "main" doc page
* new examples.md page to collect links to all at one place
* remove obsolete references from classic pages
* use akka-sample-cluster-scala as multi jvm testing sample
