Set up proguard-annotations as separate Maven artifact

Summary:
We need one place, any place really, to publish that good old `DoNotStrip` annotation
from that we currently copy across various repos, causing havoc for anybody who
tries to integrate more than one FB Android library into their project.

Yoga is very well positioned for this because it's already its own Gradle module and
all that's missing are these few lines.

Reviewed By: SidharthGuglani

Differential Revision: D16783035

fbshipit-source-id: 69b6224a725194d036c6a23a36bd76d3487b9811

java/proguard-annotations/build.gradle

@@ -6,3 +6,4 @@
  */
 
 apply plugin: 'java'
+apply from: rootProject.file('gradle/release.gradle')

java/proguard-annotations/gradle.properties

@@ -0,0 +1,12 @@
+#
+#  Copyright (c) Facebook, Inc. and its affiliates.
+#
+#  This source code is licensed under the MIT license found in the LICENSE
+#  file in the root directory of this source tree.
+#
+
+GROUP=com.facebook.yoga
+POM_NAME=Proguard Annotations
+POM_DESCRIPTION=Shared annotations for use with Proguard
+POM_ARTIFACT_ID=proguard-annotations
+POM_PACKAGING=jar