Documentation in the REST OpenAPI spec were showing incorrect information about Purchasing endpoints. Update the open api spec to reflect information about purchases, not requests.
* [maintenance] speedup integration test * [rest api] add proofProbability parameter to storage requests * [integration] negotiation test ends when contract starts * [integration] reusable 2 node setup for tests * [integration] introduce CodexClient for tests * [node] submit storage proofs when required * [contracts] Add Slot type * [proving] replace onProofRequired & submitProof with onProve Removes duplication between Sales.onProve() and Proving.onProofRequired()
Co-authored-by: Eric Mastro <github@egonat.me>