Update the Oomph setup for Eclipse 2019-06

Closes gh-15200

CONTRIBUTING.adoc

@@ -155,8 +155,8 @@ to Maven by setting a `MAVEN_OPTS` environment variable with the value
 
 
 === Importing into Eclipse
-You can import the Spring Boot code into any Eclipse Oxygen based distribution. The easiest
-way to setup a new environment is to use the Eclipse Installer with the provided
+You can import the Spring Boot code into any Eclipse 2019-06 based distribution. The
+easiest way to setup a new environment is to use the Eclipse Installer with the provided
 `.setup` file (in the `/eclipse` folder).
 
 
@@ -164,8 +164,8 @@ way to setup a new environment is to use the Eclipse Installer with the provided
 Spring Boot includes a `.setup` files which can be used with the Eclipse Installer to
 provision a new environment. To use the installer:
 
-* Download and run the latest Eclipse Installer from
-  https://www.eclipse.org/downloads/[eclipse.org/downloads/] (under "Get Eclipse").
+* Download and run the latest
+  https://www.eclipse.org/downloads/packages/installer[Eclipse Installer].
 * Switch to "Advanced Mode" using the drop down menu on the right.
 * Select "`Eclipse IDE for Java Developers`" under "`Eclipse.org`" as the product to
   install and click "`next`".

eclipse/spring-boot-project.setup

@@ -74,10 +74,18 @@
         name="org.eclipse.wst.web_ui.feature.feature.group"/>
     <requirement
         name="org.sonatype.m2e.buildhelper.feature.feature.group"/>
+    <requirement
+          name="org.springframework.boot.ide.main.feature.feature.group"/>
+    <requirement
+          name="org.springframework.ide.eclipse.boot.dash.feature.feature.group"/>
+    <requirement
+          name="org.springframework.tooling.boot.ls.feature.feature.group"/>
     <repository
         url="https://dl.bintray.com/spring/javaformat-eclipse/"/>
     <repository
         url="https://repo1.maven.org/maven2/.m2e/connectors/m2eclipse-buildhelper/0.15.0/N/0.15.0.201405280027/"/>
+    <repository
+        url="https://download.springsource.com/release/TOOLS/sts4/update/e4.12/"/>
     <description>
       Install the tools needed in the IDE to work with the
       source code for ${scope.project.label}