[SPARK-13595][BUILD] Move docker, extras modules into external

## What changes were proposed in this pull request?

Move `docker` dirs out of top level into `external/`; move `extras/*` into `external/`

## How was this patch tested?

This is tested with Jenkins tests.

Author: Sean Owen <sowen@cloudera.com>

Closes #11523 from srowen/SPARK-13595.

dev/sparktestsupport/modules.py

@@ -195,8 +195,8 @@ streaming_kinesis_asl = Module(
     name="streaming-kinesis-asl",
     dependencies=[],
     source_file_regexes=[
-        "extras/kinesis-asl/",
-        "extras/kinesis-asl-assembly/",
+        "external/kinesis-asl/",
+        "external/kinesis-asl-assembly/",
     ],
     build_profile_flags=[
         "-Pkinesis-asl",

docs/streaming-kinesis-integration.md

@@ -37,7 +37,7 @@ A Kinesis stream can be set up at one of the valid Kinesis endpoints with 1 or m
 			[region name], [initial position], [checkpoint interval], StorageLevel.MEMORY_AND_DISK_2)
 
 	See the [API docs](api/scala/index.html#org.apache.spark.streaming.kinesis.KinesisUtils$)
-	and the [example]({{site.SPARK_GITHUB_URL}}/tree/master/extras/kinesis-asl/src/main/scala/org/apache/spark/examples/streaming/KinesisWordCountASL.scala). Refer to the [Running the Example](#running-the-example) subsection for instructions on how to run the example.
+	and the [example]({{site.SPARK_GITHUB_URL}}/tree/master/external/kinesis-asl/src/main/scala/org/apache/spark/examples/streaming/KinesisWordCountASL.scala). Refer to the [Running the Example](#running-the-example) subsection for instructions on how to run the example.
 
 	</div>
 	<div data-lang="java" markdown="1">
@@ -50,7 +50,7 @@ A Kinesis stream can be set up at one of the valid Kinesis endpoints with 1 or m
 			[region name], [initial position], [checkpoint interval], StorageLevel.MEMORY_AND_DISK_2);
 
 	See the [API docs](api/java/index.html?org/apache/spark/streaming/kinesis/KinesisUtils.html)
-	and the [example]({{site.SPARK_GITHUB_URL}}/tree/master/extras/kinesis-asl/src/main/java/org/apache/spark/examples/streaming/JavaKinesisWordCountASL.java). Refer to the [Running the Example](#running-the-example) subsection for instructions to run the example.
+	and the [example]({{site.SPARK_GITHUB_URL}}/tree/master/external/kinesis-asl/src/main/java/org/apache/spark/examples/streaming/JavaKinesisWordCountASL.java). Refer to the [Running the Example](#running-the-example) subsection for instructions to run the example.
 
 	</div>
 	<div data-lang="python" markdown="1">
@@ -61,7 +61,7 @@ A Kinesis stream can be set up at one of the valid Kinesis endpoints with 1 or m
 			[region name], [initial position], [checkpoint interval], StorageLevel.MEMORY_AND_DISK_2)
 
 	See the [API docs](api/python/pyspark.streaming.html#pyspark.streaming.kinesis.KinesisUtils)
-	and the [example]({{site.SPARK_GITHUB_URL}}/tree/master/extras/kinesis-asl/src/main/python/examples/streaming/kinesis_wordcount_asl.py). Refer to the [Running the Example](#running-the-example) subsection for instructions to run the example.
+	and the [example]({{site.SPARK_GITHUB_URL}}/tree/master/external/kinesis-asl/src/main/python/examples/streaming/kinesis_wordcount_asl.py). Refer to the [Running the Example](#running-the-example) subsection for instructions to run the example.
 
 	</div>
 	</div>
@@ -190,9 +190,9 @@ To run the example,
 	</div>
 	<div data-lang="python" markdown="1">
 
-        bin/spark-submit --jars extras/kinesis-asl/target/scala-*/\
+        bin/spark-submit --jars external/kinesis-asl/target/scala-*/\
             spark-streaming-kinesis-asl-assembly_*.jar \
-            extras/kinesis-asl/src/main/python/examples/streaming/kinesis_wordcount_asl.py \
+            external/kinesis-asl/src/main/python/examples/streaming/kinesis_wordcount_asl.py \
             [Kinesis app name] [Kinesis stream name] [endpoint URL] [region name]
 
 	</div>

docker-integration-tests/pom.xml → external/docker-integration-tests/pom.xml

@@ -23,7 +23,7 @@
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.11</artifactId>
     <version>2.0.0-SNAPSHOT</version>
-    <relativePath>../pom.xml</relativePath>
+    <relativePath>../../pom.xml</relativePath>
   </parent>
 
   <artifactId>spark-docker-integration-tests_2.11</artifactId>