Static App registration / App management interface

[dmitrizagidulin]

Most identity providers that support OAuth2 / OIDC, such as Facebook, Google, Twitter, Github, etc, all have a 'Register Your App' interface. Where you perform an OAuth2 static registration, and get a client_id and client_secret tokens for your apps to use the API.

Currently, we only support the more advanced OIDC Dynamic Client Registration method, but we don't have a simple static registration app, so that you can access your data space from a CLI with curl, for example.