Add Kokoro config and script for building current structure of javadocs

.kokoro/release/publish_javadoc.cfg

@@ -0,0 +1,19 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+env_vars: {
+    key: "STAGING_BUCKET"
+    value: "docs_staging"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/google-cloud-java/.kokoro/release/publish_javadoc.sh"
+}
+
+before_action {
+  fetch_keystore {
+    keystore_resource {
+      keystore_config_id: 73713
+      keyname: "docuploader_service_account"
+    }
+  }
+}

.kokoro/release/publish_javadoc.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+# Copyright 2019 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eo pipefail
+
+if [[ -z "${CREDENTIALS}" ]]; then
+  CREDENTIALS=${KOKORO_KEYSTORE_DIR}/73713-docuploader_service_account
+fi
+
+if [[ -z "${STAGING_BUCKET}" ]]; then
+  echo "Need to set STAGING_BUCKET environment variable"
+  exit 1
+fi
+
+# work from the git root directory
+pushd $(dirname "$0")/../../
+
+# install docuploader package
+python3 -m pip install gcp-docuploader
+
+# compile all packages
+mvn clean install -B -DskipTests=true
+
+build_and_publish_site() {
+  DIRECTORY=$1
+  NAME=$1
+  VERSION=$(grep ${NAME}: versions.txt | cut -d: -f3)
+
+  pushd ${DIRECTORY}
+
+  # build the docs
+  mvn site
+  mvn site:stage -DtopSiteURL=https://googleapis.dev/java/${NAME}/${VERSION}
+
+  pushd target/staging/site/${NAME}/apidocs
+
+  # create metadata
+  python3 -m docuploader create-metadata \
+    --name ${NAME} \
+    --version ${VERSION} \
+    --language java
+
+  # upload docs
+  python3 -m docuploader upload . \
+    --credentials ${CREDENTIALS} \
+    --staging-bucket ${STAGING_BUCKET}
+
+  popd
+  popd
+}
+
+# TODO (chingor): split all the artifacts
+build_and_publish_site google-api-grpc
+build_and_publish_site google-cloud-clients