Remove now-unnecessary data path types and diagram. (#60)
Remove now-unnecessary data path types and diagram. (#60)

Motivation:

We had bold plans, but they didn't work out, so these types are now
vestigial.

Modifications:

Removed them.

Result:

Fewer types
apple/swift-nio-http2,apple/swift-nio-http2,apple/swift-nio-http2,apple/swift-nio-http2