[SPARK-15526][MLLIB] Shade JPMML

## What changes were proposed in this pull request?

Shade JPMML classes (`org.jpmml.**`) and related PMML model classes (`org.dmg.pmml.**`). This insulates downstream users from the version of JPMML in Spark, allows us to upgrade more freely, and allows downstream users to use a different version. JPMML minor releases are not generally forwards/backwards compatible.

## How was this patch tested?

Existing tests

Author: Sean Owen <sowen@cloudera.com>

Closes #18584 from srowen/SPARK-15526.

pom.xml

@@ -2363,6 +2363,7 @@
               <include>org.eclipse.jetty:jetty-util</include>
               <include>org.eclipse.jetty:jetty-server</include>
               <include>com.google.guava:guava</include>
+              <include>org.jpmml:*</include>
             </includes>
           </artifactSet>
           <relocations>
@@ -2377,6 +2378,14 @@
               <pattern>com.google.common</pattern>
               <shadedPattern>${spark.shade.packageName}.guava</shadedPattern>
             </relocation>
+            <relocation>
+              <pattern>org.dmg.pmml</pattern>
+              <shadedPattern>${spark.shade.packageName}.dmg.pmml</shadedPattern>
+            </relocation>
+            <relocation>
+              <pattern>org.jpmml</pattern>
+              <shadedPattern>${spark.shade.packageName}.jpmml</shadedPattern>
+            </relocation>
           </relocations>
         </configuration>
         <executions>