Move Requirements/Work Item PRs from wot to wot-usecases

[mmccool]

Move

• Link Discovery Work Items to Requirements wot#1186
• Deduplicate "Additional Introductions" in Discovery work items wot#1103

from wot to wot-usecases repo as a prelude to cleaning up Discovery requirements.

[mmccool]

This was merged, but need to move content to the right place: w3c/wot#1186