Drop STS plugins from Eclipse setup

Author: philwebb

eclipse/spring-boot-project.setup

@@ -90,12 +90,6 @@
         name="org.eclipse.wst.server_adapters.feature.feature.group"/>
     <requirement
         name="org.eclipse.wst.web_ui.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"/>
     <requirement
         name="org.eclipse.buildship.feature.group"/>
     <requirement
@@ -104,8 +98,6 @@
         url="https://repo.spring.io/javaformat-eclipse-update-site/"/>
     <repository
         url="https://repo.maven.apache.org/maven2/.m2e/connectors/m2eclipse-buildhelper/0.15.0/N/0.15.0.201405280027/"/>
-    <repository
-        url="https://download.springsource.com/release/TOOLS/sts4/update/latest/"/>
     <repository
         url="https://download.eclipse.org/buildship/updates/e411/releases/"/>
     <description>