Add checkstyle prebuilt jar and move checkstyle.py and related files

- This adds Checkstyle 7.4-SNAPSHOT
  Taken from internal builder:
    https://android-build.googleplex.com/builds/branch-dashboard/ub-checkstyle-master?build_id=3575892
  Built from external/checkstyle 4f80bd71c5c6647112ae74163e8548e2f44e7e98
- This moves checkstyle.py and related files from
  platform/development to this repo.

Bug: 33078621
Test: Ran checkstyle.py on some test java files.
Change-Id: I91b196fb87ad01d171bf4250ce5a2101d6890a59
diff --git a/default-javadoc-checks.xml b/default-javadoc-checks.xml
new file mode 100644
index 0000000..b17f2c6
--- /dev/null
+++ b/default-javadoc-checks.xml
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright (C) 2016 The Android Open Source Project
+  ~
+  ~ 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.
+-->
+<module name="JavadocType">
+  <property name="severity" value="warning"/>
+  <property name="tokens" value="INTERFACE_DEF, CLASS_DEF"/>
+  <property name="scope" value="public"/>
+  <property name="allowUnknownTags" value="true"/> <!-- Allows @hide tags in JavaDocs -->
+  <message key="javadoc.missing" value="Public classes and interfaces require JavaDoc comments."/>
+</module>
+<module name="JavadocMethod">
+  <property name="severity" value="error"/>
+  <property name="scope" value="public"/>
+  <property name="tokens" value="METHOD_DEF"/>
+  <property name="allowMissingParamTags" value="true"/>
+  <property name="allowMissingPropertyJavadoc" value="true"/>
+  <property name="allowMissingReturnTag" value="true"/>
+  <property name="allowMissingThrowsTags" value="true"/>
+</module>