Structure project authentication for all types of clients

[hikingc]

This is a hard one, it involves creating a whole module for handling the auth

I am not considering the addition of credential persistence logic for now as any consumer might use their own approach (disk, keyring, db), rather just implement the necessary endpoints.

The same thing can be said about the legacy password system

[hikingc]

A naive OAuth 2.0 has been implemented, but some app consumers might require automated workloads (bots for example), to make things easier to structure and build, an interface with generic methods is not coupled to the main facade so that it allows the consumers to either use the implementations that may be created in this lib or their own ones.