User Stories in Work Item Descriptions

[egekorkan]

Created in the TD call using w3c/wot-usecases#305

[egekorkan]

Discussed in the UC call:

• These simple User Stories should link to a high-level use case or category, i.e. "Greenhouse IoT Devices". This link should be provided by the submitter.
• The user stories would be the high-level requirements in the Use Cases and Requirements document. This will be cop
• The motivation text that we see in Reduce intrinsic protocol level redundancy #1248 (comment) would go into the TD spec so that the readers get a backstory of the feature.
• There should be a general information on where to find the use case and requirements on that feature. That way, we do not need to maintain bidirectional links. We need to think of an easy way to do that for us, while also being clear to the reader.

[egekorkan]

In the TD call, we have decided to merge the PR. @TallTed if you have any suggestion improvements, please let us know. Otherwise, this PR will be merged asynchronously.