Also sort by last updated date

When I sorting I would like to be able to sort by the last "updated" date e.g. https://github.com/clearlydefined/service/blob/0a568eeed979d1edfb96480b1dd1b7138dbd39b2/schemas/definition-1.0.json#L53

See also #464 and #465 (and #386 as this would be eventually needed for some API-based sync)

Start by reading schemas/definition-1.0.json around line 53, then review related issues #464, #465, and #386 to understand the expected updated-date field and sorting use cases. Done means the service supports sorting by the last updated date in the requested context, with behavior consistent with those related requirements.

Written by the indexing model from the issue text.