Allow for dynamic scope definition via api

[eabili0]

The scopes Whisper can handle today are defined in build time.

It would be interesting to have them defined in runtime, via API, so Whisper registered Clients can inform their own scopes.

[claudiosegala]

@abilioesteves just to check, these are the steps for this issue:

1. Create a Scopes Table for scopes definitions;
2. Seed the current default scopes during the build;
3. Improve the retrieval of scopes to retrieve from the database;
4. Create an API to CRUD the Scopes Table;

PS: Scopes Table fields would be ClientID, Description, Alias, Details, Scope and ID. ClientID would be nullable so that null meant that this scope is for all.
PS2: Someone can only edit/delete Scopes that have the same client id.

[eabili0]

@claudiosegala, this issue is now part of a more broad Milestone. The applications will now be registered by the user through a Whisper dashboard.

The proposed Scopes Table will have a n:1 relationship with an Applications Table.

For that reason, I'm sunsetting this issue. The efforts will now be redirected to issues #59 and #58 .

Thanks!