Docker Integration

[ab7289]

User story
As a maintainer, I want the travis build to push newly built docker images to docker hub when the master branch builds.

Currently, it is only configured to push the image on the mercury-telemetry/mercury-telemetry repository, which will never be the case. It should instead push the image when the repo is mercury-telemetry/mercury-hardware:master.

Additionally the secure key for the REGISTRY_PASS environment variable will need to be regenerated by someone with rights.

Acceptance criteria

Definition of Done
I will know this is done when the docker image is pushed to docker hub on deployment of the mercury-hardware master branch and the secure env var is updated.