PermissionsApi for Agent, permissions API for Web5 (#833)

This refactors a lot of what's in #824 with regards to creating/fetching grants.

Satisfies: #827

Introduces a `PermissionsApi` interface and an `AgentPermissionsApi` concrete implementation.

The interface implements the following methods `fetchGrants`, `fetchRequests`, `isGrantRevoked`, `createGrant`, `createRequest`, `createRevocation` as convenience methods for dealing with the built-in permission protocol records.

The `AgentPermissionsApi` implements an additional static method `matchGrantFromArray` which was moved from a `PermissionsUtil` class, which is used to find the appropriate grant to use when authoring a message.

A Private API usedin a connected state to find and cache the correct grants to use for the request.

A Permissions API which implements `request`, `grant`, `queryRequests`, and `queryGrants` that a user can utilize

The `Web5` permissions api introduces 3 helper classes to represent permissions:
 Class to represent a permission request record. It implements convenience methods similar to the `Record` class where you can `store()`, `import()` or `send()` the underlying request record. Additionally a `grant()` method will create a `PermissionGrant` object.

 Class to represent a grant record. It implements convenience methods similar to the `Record` class where you can `store()`, `import()` or `send()` the underlying grant record. Additionally a `revoke()` method will create a `GrantRevocation` object, and `isRevoked()` will check if the underlying grant has been revoked.

 Class to represent a permission grant revocation record. It implements convenience methods similar to the `Record` class where you can `store()`  or `send()` the underlying revocation record.

packages/api/tests/dwn-api.spec.ts

@@ -46,10 +46,6 @@ describe('DwnApi', () => {
     // Instantiate DwnApi for both test identities.
     dwnAlice = new DwnApi({ agent: testHarness.agent, connectedDid: aliceDid.uri });
     dwnBob = new DwnApi({ agent: testHarness.agent, connectedDid: bobDid.uri });
-
-    // clear cached permissions between test runs
-    dwnAlice['cachedPermissions'].clear();
-    dwnBob['cachedPermissions'].clear();
   });
 
   after(async () => {