Add a python binary to generate the protobuf for care_map

This binary parses the legacy care_map text in the input file and writes
the generated protobuf message into the output file. For test purpose,
it also has a "--parse_proto" option to reverse the process and convert
a protobuf message file into plain text.

The build script will then call the binary to generate the care_map.txt
in the new format.

Bug: 77867897
Test: Run the binary to convert a care_map.txt, run update_verifier
Change-Id: I3ca65e19027404806132aa8d51e9bff766630c99