Introduce PublishDocsRules (Part1)

So we can build docs from already released artifacts; also it allow us
to create config for different subprojects etc

Test: ./gradlew publicDocsTask
Change-Id: I09fc7364747fdf184db31a262493b9a070686674
diff --git a/settings.gradle b/settings.gradle
index e73df47..059a289 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -222,3 +222,10 @@
 ///// FLATFOOT START
 
 ///// FLATFOOT END
+
+// fake project which is used for docs generation from prebuilts
+// we need real android project to generate R.java, aidl etc files that mentioned in sources
+if (!startParameter.projectProperties.containsKey('android.injected.invoked.from.ide')) {
+    // we don't need it in ide, so we don't configure it there
+    includeProject(":docs-fake", "docs-fake")
+}