+str #16038 Create Source/Flow/Sink from partial flow graphs
Merge pull request #16061 from akka/wip-graphs-as-source-flow-sink-ban

+str #16038 Create Source/Flow/Sink from partial flow graphs
!htc #15726: Akka HTTP with the new DSL
Added some sugar
ported rest of Http
big FlowMaterializer removal
Fixing comments