add relations between economic and regulatory instruments

[amanda-wein]

Description of the issue

(comments from Silvia Weko)

There are also some other economic instruments MAY be affected by regulatory ones:

• you can have “public procurement” without a “public procurement standard”, but if “public procurement exists” it conditions public procurement
• you can have “auction with market premium” without “tendering scheme standard”, but if “tendering scheme standard” exists it conditions auctions

Workflow checklist

• I am aware of the workflow in CONTRIBUTING.md

[amanda-wein]

Hold off on working on this issue until #10 is resolved, since that issue may involve changing the auction definition.

[silviaweko]

See other issue - maybe "complies with" - ?