Add Prerequisites for Operations to Core

[JefWight]

Some operations have certain requirements of the entity they are being executed on in order to succeed.

For example, a service managing email may expose a Send operation on a EmailDraft, but sending the email may require at least one of To:, CC:, or BCC: have a value set. We would like the ability to express these requirements as their own annotation (distinct from Description).

[ralfhandl]

Hi Jeff,

I'd like to continue this discussion on the odata-comment mailing list.

Thanks in advance!
--Ralf

[ralfhandl]

See https://lists.oasis-open.org/archives/odata-comment/201510/msg00007.html