Implement Oauth endpoint in API server (for Globus)

Per the https://opensource.ncsa.illinois.edu/confluence/display/NDS/Revised+Authentication+Design, implement the basic "wbauth" provider.

Requirements:

• Serves as nginx auth_request handler for use with Kubernetes Nginx ILB
• Serves as upstream to oauth2_proxy
  • Upon successful authentication via Globus, either:
    • Check JWT
    • Create account information
    • Update account information
    • Generate JWT cookie
• Unit tests