Cleanup ToC, #22901

* remove old intro / getting started
* other modules, community projects

akka-docs/src/main/paradox/java/hello-world.md

@@ -1,21 +0,0 @@
-# The Obligatory Hello World
-
-The actor based version of the tough problem of printing a
-well-known greeting to the console is introduced in a ready to run [Akka Main sample](@exampleCodeService@/akka-samples-main-java)
-together with a tutorial. The source code of this sample can be found in the
-[Akka Samples Repository](@samples@/akka-sample-main-java).
-
-The tutorial illustrates the generic launcher class `akka.Main` which expects only
-one command line argument: the class name of the application’s main actor. This
-main method will then create the infrastructure needed for running the actors,
-start the given main actor and arrange for the whole application to shut down
-once the main actor terminates.
-
-There is also a [Gitter8](http://www.foundweekends.org/giter8/) template in the same problem domain
-that is named [Hello Akka!](https://github.com/akka/hello-akka.g8).
-It describes the basics of Akka in more depth. If you have *sbt* already installed, you can create a project
-from this template by running:
-
-```
-sbt new akka/hello-akka.g8
-```

akka-docs/src/main/paradox/java/http/index.md

@@ -1,4 +0,0 @@
-# Akka HTTP Documentation (Java) moved!
-
-Akka HTTP has been released as independent stable module (from Akka HTTP 10.x onwards).
-The documentation is available under [doc.akka.io/akka-http/current/](http://doc.akka.io/docs/akka-http/current/java.html).

akka-docs/src/main/paradox/java/index-utilities.md

@@ -10,6 +10,5 @@
 * [../scala/common/duration](../scala/common/duration.md)
 * [../scala/common/circuitbreaker](../scala/common/circuitbreaker.md)
 * [extending-akka](extending-akka.md)
-* [../scala/intro/deployment-scenarios](../scala/intro/deployment-scenarios.md)
 
 @@@

akka-docs/src/main/paradox/java/intro

@@ -1 +0,0 @@
-../scala/intro

akka-docs/src/main/paradox/java/scala-compat.md

@@ -1,5 +1,11 @@
 # Java 8 and Scala Compatibility
 
+## Scala and Java APIs
+
+Akka has both a @ref:[Scala Documentation](../scala.md) and a @ref:[Java Documentation](../java.md).
+
+## Java 8 types
+
 Starting with Akka 2.4.2 we have begun to introduce Java 8 types (most
 prominently `java.util.concurrent.CompletionStage` and
 `java.util.Optional`) where that was possible without breaking binary or

akka-docs/src/main/paradox/java/stream/stream-quickstart.md

@@ -3,7 +3,7 @@
 # Quick Start Guide
 
 Create a project and add the akka-streams dependency to the build tool of your
-choice as described in @ref:[Using a build tool](../../scala/intro/getting-started.md#build-tool).
+choice as described in @ref:[Using a build tool](../../java/guide/quickstart.md).
 
 A stream usually begins at a source, so this is also how we start an Akka
 Stream. Before we create one, we import the full complement of streaming tools: