Extend User API functionality

[pplanel]

We need to extend the features of the API to enable full user management.
So I'm creating this issue to understand if this is a feature that the pkp-lib project would find usable and guidelines to implement it.

Describe the solution you'd like
Some sort of guidance to get the project vision about the issue.

Who is asking for this feature?
Journal

Additional information
There is two ways that I'm envisioning:

1. Extend the pkp-lib API to allow user management
2. Create an SDK for integration on third-party applications to interact with pkp-lib (OJS in my specifics)

Thanks

[asmecher]

@pplanel, for the API work, have you run across OJS's Swagger documentation? See docs/dev/swagger.yaml in a git checkout or by browsing https://github.com/pkp/ojs for the appropriate tag/branch. (The document is not shipped with OJS so you won't find it inside the .tar.gz file.) That's the place to start -- if you've got additional endpoints you'd like to propose, it would probably make sense to propose them as additions to that.

For the SDK, can you describe what you're looking for in more detail?