Add `interop:grantedBy` predicate on data grants

[srosset81]

As discussed on Friday with @elf-pavlik

This is required for delegated data grants, otherwise we can't know who has created the grant.

[srosset81]

@elf-pavlik Shouldn't we have something equivalent for data authorizations as well, like interop:authorizedBy ?
Data authorizations have a interop:dataOwner predicate so, in the case of delegation, we are supposed to create one data authorization per data owner. But then we have no information about the user who is granting the authorization, even if we could assume it is the storage owner.

[elf-pavlik]

Data Authorizations have a interop:dataOwner predicate

It is not always used, for example not with scope AllFromAgent, I still need to think how to add AllFromRole scope as we start adding roles.

But then we have no information about the user who is granting the authorization

authorizedBy sounds reasonable, Access Authorization is using grantedBy maybe we can just reuse this one. We will also need to look at it more closely when we get to organization admins and Trusted Grants, If they act on behalf or organization grantedBy would be the organization, if they delegate their personal access it would be the admin.

The general rule, which we should state in normative way, is that grantee of the grant that is being delegated, becomes grantedBy on the delegated grant. dataOwner always stays the same throughout the whole delegation chain.

[srosset81]

OK, then let's add interop:grantedBy to data authorizations as well :-)

[elf-pavlik]

OK, then let's add interop:grantedBy to data authorizations as well :-)

Actually we were already doing it in #304 I will see if it's easier to handle it as one or two separate PRs

[elf-pavlik]

I updated #304 and marked it as ready for review