Update all play2-java benchmark projects

[mkurz]

This pull request upgrades all the play2-java projects to the latest Play version. Play now uses akka-http by default.

I have three questions:

• Will there be another preview round?
• The TechEmpower benchmark environment uses 2 x 4-Core E5520 CPUs in the database server - so that is 8 physical cores? Is that correct? (Needed for db pool and thread pool sizing)
• How can I change the name of the benchmark project in the result table? It looks like e.g. "display_name": "play2-java-jpa-hikaricp" from the benchmark_config.json does not get picked up, instead I see this:
  
  Why is the project named play-java-jpa? I can not figure out how that name is composed...

[NateBrady23]

• There will probably be a couple more preview rounds, since we had some longer than expected downtime
• Yes, 16 Hyperthreaded cores / 8 physical cores
• I believe we have a hard-coded map of frameworks on the results site to create smaller links for sharing filtered links. I'll see if we can get that updated for you

[mkurz]

@nbrady-techempower Thanks for your answers!

[wsargent]

@mkurz https://github.com/tenorviol/play-c100k-test may be useful as a reference as well -- I added a pull request for native option: tenorviol/play-c100k-test#1