Play Framework

Migrate server transport from Netty 3.10 to Netty 4.2 (Stage A)

Replaces the bundled netty-3.10.6.Final.jar with the modular Netty 4.2.12
artifacts (buffer, codec-base, codec-http, common, handler, resolver,
transport) and ports the server-side glue to the Netty 4 API:

- Server.java: ServerBootstrap now uses bossGroup/workerGroup
  EventLoopGroups + NioServerSocketChannel.class instead of the Netty 3
  NioServerSocketChannelFactory + Executors pair. childOption(TCP_NODELAY)
  replaces setOption("child.tcpNoDelay").
- HttpServerPipelineFactory / SslHttpServerPipelineFactory: now extend
  ChannelInitializer<Channel> (replacing ChannelPipelineFactory). Default
  pipeline switched from play.server.StreamChunkAggregator to the stock
  io.netty.handler.codec.http.HttpObjectAggregator with a 1 MB cap
  (configurable via play.netty.maxContentLength). Reflective handler
  construction now special-cases HttpObjectAggregator's int-arg ctor.
- Deletes StreamChunkAggregator and FileChannelBuffer (Netty 3-only).
- FileService, SslPlayHandler, NettyPlayChannel, Http, F: package moves
  org.jboss.netty.* -> io.netty.* and the corresponding API shifts.
- application-skel/conf/application.conf: documented default pipeline
  updated to the io.netty.* class names with HttpObjectAggregator.

Stage A intentionally caps aggregated request bodies at 1 MB; Stage B
(PF-32) will restore disk-spooling for large uploads.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>