Fix presubmit jobs in appengine-plugins

cleanup top-level README.md to list the modules

The README in appengine-plugins-core module had the same content
as the top-level README. This change fixes the duplication.

Change-Id: Ibc8bede49a098575e2742dae7f9a43c1a0a91ee9

.kokoro/continuous.bat

@@ -3,7 +3,7 @@
 REM Use Java 8 for build
 echo %JAVA_HOME%
 
-cd github/appengine-plugins
+cd git/appengine-plugins
 
 if not exist "%HOME%\.m2" mkdir "%HOME%\.m2"
 copy settings.xml "%HOME%\.m2"

.kokoro/continuous.sh

@@ -8,7 +8,7 @@ set -x
 sudo /opt/google-cloud-sdk/bin/gcloud components update --quiet
 sudo /opt/google-cloud-sdk/bin/gcloud components install app-engine-java --quiet
 
-cd github/appengine-plugins
+cd git/appengine-plugins
 
 # Use GCP Maven Mirror
 mkdir -p ${HOME}/.m2

.kokoro/continuous_mac.sh

@@ -23,7 +23,7 @@ tar -xzf apache-maven-3.5.0-bin.tar.gz
 M2_HOME="$(pwd)"/apache-maven-3.5.0
 PATH=$PATH:$M2_HOME/bin
 
-cd github/appengine-plugins
+cd git/appengine-plugins
 
 # Use GCP Maven Mirror
 mkdir -p ${HOME}/.m2

.kokoro/release_build.sh

@@ -5,7 +5,7 @@ set -e
 # Display commands to stderr.
 set -x
 
-cd github/appengine-plugins
+cd git/appengine-plugins
 
 # Use GCP Maven Mirror
 mkdir -p ${HOME}/.m2

README.md

@@ -1,91 +1,10 @@
-This repository hosts the Google App Engine Maven and Gradle plugins.
+This repository hosts the Google App Engine Maven and Gradle plugins:
 
-User documents:
+- [app-maven-plugin](./app-maven-plugin): [App Engine Maven Plugin user document](https://cloud.google.com/appengine/docs/standard/java-gen2/using-maven)
+- [app-gradle-plugin](./app-gradle-plugin): [App Engine Gradle Plugin user document](https://cloud.google.com/appengine/docs/standard/java-gen2/using-gradle)
+- [appengine-plugins-core](./appengine-plugins-core): This is a shared utility library for the two above.
 
-- [App Engine Maven Plugin](https://cloud.google.com/appengine/docs/standard/java-gen2/using-maven)
-- [App Engine Gradle Plugin](https://cloud.google.com/appengine/docs/standard/java-gen2/using-gradle)
+## Requirements
 
-# Google App Engine Plugins Core Library
-
-![experimental](https://img.shields.io/badge/stability-experimental-red.svg)
-
-IMPORTANT:
-This library is used by Google internal plugin development teams to share App Engine
-related code. Its use for any other purpose is highly discouraged and unsupported.
-Visit our [App Engine documentation](https://cloud.google.com/appengine/docs/admin-api/)
-for more information on Google supported clients for App Engine administration.
-
-# Requirements
-
-This library requires Java 1.8 or higher to run.
-This library requires Maven and Java 1.8 or higher to build.
-
-You must also install the Cloud SDK command line interface (gcloud). If it isn't installed yet, follow [these instructions](https://cloud.google.com/sdk/).
-
-You must also install the app-engine-java component:
-
- gcloud components install app-engine-java
-
-# Supported operations
-
-The library implements the following operations:
-
-* Deploy an application to standard or flexible environment
-* Stage an application for deployment
-* Run an application on the local server synchronously or asynchronously
-
-# How to use
-
-Build the library using the "mvn clean install" command at the repository root directory, where the pom.xml file is located. This produces the appengine-plugins-core-*version*-SNAPSHOT.jar file in the "target" directory that you can add to your application's class path.
-
-To deploy a new version, a client calls the library in the following way:
-
-```java
-// All operations require the cloud SDK
-CloudSdk cloudSdk = new CloudSdk.Builder().sdkPath(some-path).javaHome(some-java-home).build();
-
-
-// Operations that use gcloud command line are initiated by the Gcloud object.
-Gcloud gcloud = Gcloud.builder(sdk).setMetricsEnvironment("asdf","12").setCredentialFile(some-file).build()
-
-// Similarly for AppCfg and the DevAppServer
-AppCfg appcfg = AppCfg.builder(sdk).build()
-DevServers localRun = DevServers.builder(sdk).build()
-
-// Operations are started as processes, access to these processes is handled
-// by implementations of ProcessHandler. To continue to interface with processes
-// as before, use LegacyProcessHandler.
-ProcessHandler handler = LegacyProcessHandler.builder()...configureHandler...build();
-gcloud.newDeployment(handler).deploy(myDeployConfiguration);
-```
-
-## SDK Manager
-
-This library provides a mechanism for installing, adding components to, and updating the Cloud SDK. The operations are intended to run asynchronously, either on an executor or through mechanisms provided by an IDE.
-
-```java
-// Create a new Managed SDK instance
-ManagedCloudSdk sdk = ManagedCloudSdk.newManagedSdk("123.123.123") // SDK fixed at version.
-ManagedCloudSdk sdk = ManagedCloudSdk.newManagedSdk() // 'LATEST' sdk, can be updated.
-
-// Implement the listener interface to listen to operation output
-MessageListener listener = new MessageListener() {...};
-
-// Always check if operations are needed before running them
-if (!sdk.isInstalled()) {
- sdk.newInstaller().install(listener);
-}
-
-// use SdkComponent to reference a Cloud Sdk component
-if (!sdk.hasComponent(SdkComponent.APP_ENGINE_JAVA)) {
- sdk.newComponentInstaller().installComponent(SdkComponent.APP_ENGINE_JAVA, listener);
-}
-
-// updates will only occur on 'LATEST' sdks
-if (!sdk.isUpToDate) {
- sdk.newUpdater().update(listener);
-}
-
-// You can then create an SDK from a managed SDK instance
-new CloudSdk.Builder().sdkPath(sdk.getSdkHome())...;
-```
+The libraries in this repository require Java 1.8 or higher to run.
+This repository requires Maven and Java 1.8 or higher to build.