Integrate validator

[eFrane]

Integrate OParl/validator into the website. This is depends on #29,
because we can't run the validator without liboparl present.

The validation flow on the website should be as follows:

1. A user enters an endpoint url to be validated and an email
   address at which they want to be notified once validation
   completes.
2. The information is enqueued and eventually processed by
   a validation job
3. The results of the validation are stored for further processing
   and formatted into a neat email for the customer.