Add missing ResourcePolicyService

[AlexanderS]

This adds the missing ResourcePolicyService. The call to this.collectionDataService.findByHref only succeeds, because the full href is used and typescript does not check the return type.

I do not know if the resouce-policy.service.ts file should be placed in something like src/app/core/authz/, but it's only a single file.

[artlowel]

Thanks @AlexanderS !

Would you mind writing a spec file for resource-policy.service.ts? It doesn't have to be very complicated, just make sure that every new method is covered.

@atarix83 Since this is a change to the submission, and you know a lot more about its inner workings than I do, perhaps you could give it a review?

[atarix83]

Thanks @AlexanderS for this PR and thanks @artlowel to mention me

@AlexanderS
you have created a DataServiceImpl both for MetadataSchemaDataService and ResourcePolicyService. Is this delegation strictly necessary? If so I should separate classes in separated file as raccomended in Angular style guide https://angular.io/guide/styleguide#single-responsibility.

other than this there is a TypeScript error in resource-policy.service.spec.ts file to resolve

[AlexanderS]

@atarix83 I just fixed the typescript error.

The DataServiceImpl stuff was just inspired by the DSpaceObjectDataService (see this conversation with artlowel) I can revert this change and remove the delegation and directly extending DataService again, if you like.

[atarix83]

@AlexanderS thanks for solving the typescript error.

I hadn't seen the conversation with @artlowel, since we already have similar implementations please leave the code as it is although we do not follow Angular style guide

[artlowel]

Thanks @AlexanderS!

LGTM

@atarix83 you're right, these DataServiceImpl classes technically violate that rule in the style guide. But I don't think they violate the spirit of the rule: that each file should do one thing. All @AlexanderS did was split the code that was in that file anyway into a private and a public part.

While we could move that DataServiceImpl class to a separate file, it should never be used by anything other than ResourcePolicyService, so there isn't much of a point in my opinion.