=pro Upgrade akka-stream dependencies to akka 2.3.3

* Upgrade dependency to akka 2.3.3
* Remove javadsl.Pair and javadsl.Predicate in favor of akka.japi.*
+str #15088, #15200: Add takeAndTail and concatAll
+ben #15064 v. simple JMH benchmark for akka streams (map, 5map)
Merge pull request #15272 from ktoso/ben-naive-stream-benchmark

=ben #15064 initial example akka-streams bench (map, 5 maps)
Merge pull request #15226 from drewhk/wip-15088-concatall-take-tail-drewhk

ConcatAll and TakeAndTail
Merge pull request #15268 from akka/wip-upgrade-stream-dependencies-to-akka-2.3.3-ban

=pro Upgrade akka-stream dependencies to akka 2.3.3
=scr silence curl on jenkins, no need for progress bars
Merge pull request #15275 from ktoso/silent-curl-for-jenkins

=scr silence curl for github tagging
+tes added AkkaMetricsKit to ease use with AkkaSpec
+ Improved printing when running from a spec (use info stead of
println), so the results appear after the test name, not before it like
it happens with unbuffered println()
=per #15064 persistence perf spec is now MetricsKit aware