Add external/annotation-tools project to master branch

Bug: 64930165

default.xml

@@ -80,6 +80,7 @@
   <project path="external/adt-infra" name="platform/external/adt-infra" groups="adt-infra,notdefault,pdk-fs" />
   <project path="external/android-clat" name="platform/external/android-clat" groups="pdk" />
   <project path="external/androidplot" name="platform/external/androidplot" groups="pdk" />
+  <project path="external/annotation-tools" name="platform/external/annotation-tools" groups="pdk" />
   <project path="external/ant-glob" name="platform/external/ant-glob" groups="pdk" />
   <project path="external/antlr" name="platform/external/antlr" groups="pdk" />
   <project path="external/apache-commons-math" name="platform/external/apache-commons-math" groups="pdk" />