Sunset interplay

[ignasi35]

It'd be good to stop depending on Interplay. Maintaining scala cross versions, having to move upstream (from play-foo to interplay) for each imrpovement, etc... is becoming more of a blocker than a benefit.

Each downstream project should inherit whichever pieces of interplay it deems necessary and maintain them separately. Here's a list of projects using interplay:

• playframework
  Copy interplay into main repository playframework#11987
• omnidoc
  Drop interplay omnidoc#268
• play-doc
  Drop interplay play-doc#206
• scalatestplus-play
  Drop interplay scalatestplus-play#447
• play-socket.io
  Drop interplay play-socket.io#214
• play-slick
  Drop interplay play-slick#773
• anorm
  Drop interplay anorm#587

No longer use interplay:

1. • play-json --> already uses its own copy of Omnidoc.scala
2. • twirl --> already uses its own copy of Omnidoc.scala
3. • play-soap

EOL projects that refer to interplay (false positives):

1. • play-native-loader --> archived EOL
2. • play-spring-loader --> archived EOL
3. • play-enhancer --> archived EOL
4. • play-iteratees --> archived EOL

[ihostage]

play-soap already done ✅

[ihostage]

@mkurz I finished the work on this. Can you review? 😉
Or just we can merge these PR's without review and I will fix problems in the future if something is wrong at release.

[mkurz]

Done, repo will be archived now.