Add SSL support to ooni-backend
This issue was automatically migrated from github issue https://github.com/TheTorProject/ooni-probe/issues/187.
We should have support for HTTPS connection to the ooni-backend.
We should have a way of pinning certain certificates inside of ooni-probe or provide a URL that is self authenticating (something like https://HASH_OF_PUBKEY@SOME_IP).