Add ability to login without creating a jetty session

[gbbirkisson]

This is for the case when we want to 'log a user' in for the scope of only 1 request. Another way to put it is to set the context for the request.

This is helpful when authenticating users with JWT's.

Options that are available:

• Extend authLib.login method to do this.
• Create authLib.setUser method.
• Create contextLib.setContext method.

[gbbirkisson]

It has been decided to add a scope parameter to the login method. Scope can be:

• SESSION
• REQUEST