added role based security plumbing

[JordanVanGogh]

Plumbing voor role based security. Implement Security/IAuthorizationProvider and provide an instance in the options when starting the scheduler.

We use this in combination with Azure Active Directory. If this PR gets accepted I'll provide an example application for Azure AD.

[maldworth]

if @jlucansky is busy (this is open source afterall, people often contribute out of their own spare time), perhaps he'd be open to putting @JordanVanGogh as a contributor to the project? Both his PR's open actually have features I'd be interested in using.