KUDU-712 (part 4): add a script to generate MDL
KUDU-712 (part 4): add a script to generate MDL

This adds a simple python script to generate an MDL file. I manually ran this
through the MDL validator. When we hook this into the CSD build process later,
we can also add a unit test to run the validator automatically on any change.

Change-Id: I4512a601032be7dc20ea2efa0ca592995ddb85b0
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/6611
Reviewed-by: Adar Dembo <866ca730bfc7f544e3ebce604ceeba4879f23df0@cloudera.com>
Tested-by: jenkins

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