Add script to parse VehicleProperty.aidl to CSV.

Allow parsing the VHAL property definitions/annotations in
VehicleProperty.aidl into a CSV file so that we can generate
documentation.

Test: python generate_annotation_enums.py --output_csv /tmp/prop.csv
Bug: 288331747
Change-Id: Icc5d023c8efdc01ead220313d6a7c66d22c63a0a