Rationale: it was already a very thin wrapper
around Marketplace, and now that its remaining
functionality has been moved to Proofs and
Marketplace, we no longer need it.
Rationale: in practice, a ProofId was always a slot id, and
an EndId was always a request id. Now that the definitons
of SlotId and RequestId are separated from the Marketplace,
we can import and use them.
- Marketplace tests for requestsForHost, and additional tests for myRequests and mySlots
- Added Utils lib with tests
- Added additional Bytes32AddressSetMap.keys expectations
Add `Bytes32AddressSetMap` which maps addresses to a requestId. This is used in `Marketplace.activeRequestsForHost`, where all addresses for a particular requestId are listed. This can then be used to iterate and list out the actives requests for a particular address in a view function only. This allows for all addresses for a request to be cleared in situations such as when a request fails or is cancelled.
Reinstate the index mapping for `activeSlots`, however with a modified data structure. The main difference comes from a change in `mySlots`: it now requires a `RequestId` as a parameter (which can be obtained using `myRequests`. This allowed for the `activeSlots` mapping to be keyed on `RequestId`, which gives a mapping of `ActiveSlotId => EnumerableSet.Bytes32`. `ActiveSlotId` is a keccak hash of `address + activeSlotIdx`, which not only allows retrieval of all active slot ids per request, but also allows clearing of all active slot ids for a request by incrementing the `activeSlotIdx`.
```
requestId => [ keccak(address + activeSlotIdx) => EnumerableSet.Bytes32 ]
```
Instead, iterate all active slots and remove them individually, only if they are part of a specific request. This is only for the case of request failure.
Allow for clearing of active slots by host, by incrementing an mapping index. The new index points to a fresh instance of EnumerableSet, effectively wiping it clean.