Numerous Course Validation Script Updates

- Added support for basic auth
- Logging into LMS (instead of using auto-auth)
- Added support for multiprocessing (runtime is down to 5 minutes from 25!)
- Retrieving courses from Insights homepage
- Logging to both console and file
- Writing CSV upon process failure

@rocha @dsjen 
I would prefer to use more specific examples than example.org or localhost as they clearly demonstrate what should be provided. Given that these will be overridden by most users, I think it's fine to have edX-specific values.