Draft: Add all exchange reciprocals, exchange groupings

Removed ProposedIntent, added reciprocal relationship instead. Should the bridging file exist any more?

Added other reciprocals to match: Agreement to Commitment, Agreement to EconomicEvent, RecipeExchange to RecipeFlow.

Added purpose to Proposal, to make more clear and explicit offer/request (and maybe other things in the future). Didn't change the existing logic, if it is shown somewhere.

Added ProposedList as a grouping of Proposals. Didn't do the params.

Added AgreementBundle as a grouping of Agreements. Didn't do the params.

Note: I've also added some explicit inverses to VF, and am not sure how to fit them into the graphql. Noting also the graphql spec will support different modeling in technologies (which is why the inverses). Perhaps some discussion, unless you feel confident?

Usual note: Please check that things are where they should be, and complete as needed for the graphql processing, etc. Thanks!