GDDI11 — Explicitly define default values in the GDDI Dictionary

The GDDI standard supports backward compatibility where an endpoint that implements a newer minor-version Type Block, containing newly added TLV(s), can receive GDDI messages with an older minor-version Type Block that does not contain those newly added TLV(s). In this case the receiving endpoint needs to assign those value(s) to a default. Currently, the convention is to define a default value for each TLV in the 'description' field within the GDDI Dictionaries via the following format: "(Default: <VALUE>)". This requires the receiving GDDI endpoint to parse-out each default value instead of having its own field. Consider adding a dedicated field for this Default Value to explicitly define it.