=doc port over some http documentation from the scala side

akka-docs-dev/rst/java/http/introduction.rst

@@ -0,0 +1,28 @@
+Introduction
+============
+
+The Akka HTTP modules implement a full server- and client-side HTTP stack on top of *akka-actor* and *akka-stream*. It's
+not a web-framework but rather a more general toolkit for providing and consuming HTTP-based services. While interaction
+with a browser is of course also in scope it is not the primary focus of Akka HTTP.
+
+Akka HTTP follows a rather open design and many times offers several different API levels for "doing the same thing".
+You get to pick the API level of abstraction that is most suitable for your application.
+This means that, if you have trouble achieving something using a high-level API, there's a good chance that you can get
+it done with a low-level API, which offers more flexibility but might require you do write more application code.
+
+Akka HTTP is structured into several modules:
+
+akka-http-core
+  A complete, mostly low-level, server- and client-side implementation of HTTP (incl. WebSockets)
+
+akka-http
+  Higher-level functionality, like (un)marshalling, (de)compression as well as a powerful DSL
+  for defining HTTP-based APIs on the server-side
+
+akka-http-testkit
+  A test harness and set of utilities for verifying server-side service implementations
+
+akka-http-jackson
+  Predefined glue-code for (de)serializing custom types from/to JSON with jackson_
+
+.. _jackson: https://github.com/FasterXML/jackson