Write only management API for User and Group resources

[refs]

What?

Essentially a write-only management API for User and Group resources. The CS3 API already provides the means for retrieving information for resources such as users and groups but it does not dictate how such resources are created. These minimal changes would add a different write layer to an administration API that would deal with destructive actions. Ultimately admin actions MUST only be taken by users with the role of administrator.

Adding roles will not be yet accounted for in this patch, and implementations should instead rely on their own logic to deal with roles, but a PR will follow up that would add roles to the CS3 API.

Design Choices

• Namespace (separate) users from groups write/delete operations instead of delegating all to a single Admin API. I considered this as an approach taken in places such as identity.
• Write operations SHOULD always return the latest version of a resource, therefore Write methods are required to return a whole Group and User resource.
• No special status codes needed to be added considered the minimal additions.

[ishank011]

@refs can you run make and push? That'll generate the documentation

[refs]

thanks for the review! good catch with the offset attribute ^^

[ishank011]

LGTM, but would more descriptive method names be helpful? Eg, CreateGroup, AddUserToGroup?

[refs]

Oh, I was thinking the same, then did a little read on Google's guidelines and left the namespace be more explicit. BUT apparently I did not have a look at the examples which explicitly append the resource name to the method haha, let me amend the changes

[refs]

@ishank011 just renamed the methods to stick to these guidelines 👍