=act fixed typo in scaladoc, and => an

Thanks @geoffjentry for spotting this :-)
=doc #15207 add note about UndeclaredThrowableException when used from Java
+per #13815 akka-persistence-tck based on @krasserm's work

Original here: https://github.com/krasserm/akka-persistence-testkit

New features:
* merged martin's tests
* usable from java (junit 4)
* simple bench test, which helps checking if ordering is perserved under
  bigger workloads and simple perf checking
* does NOT include tests for already deprecated features (deleteMessages)
* docs

Resolves #13815
+tes #12681 add EchoActor
=ben #15520 update persistence benchmark to be more relevant

Thanks @hepin1989 for noticing it got outdated a bit.

Resolves #15520
=per do not run perf spec on jenkins, just validate compilation
+doc #15537 add Typed router pattern
=ben #15544 add AtLeastOnceDelivery benchmark

drop every 11 message
change the redelivery duration per 2 seconds

change to more meaningful timeout

1,change dataCount to integer
2,add default case
3,clean up

noting follow the arrow