Port oohelperd deployment over to new pattern

[hellais]

This is about doing the following:

• Creating dockerfile for oohelperd, see: https://github.com/ooni/backend/pull/827
• Creating codebuild/codepipeline buildspec to build and deploy it, see: https://github.com/ooni/backend/pull/827
• Adding relevant modules to ooni/devops to deploy the oohelperd to a new ECS cluster following the template of how we did it for ooniapi-services. We should copy those modules and customize them to deploying this golang image.

For the last point we should follow the template of:

• ooniapi_service
• ooniapi_service_deployer And make use of ecs_cluster modules to create:
• oonith_service
• oonith_service_deployer

to create a ECS task definition and builds the dockerfile I wrote above to deploy to a new ecs_cluster the oonihelperd test helper

[hellais]

This reason why this is urgent is that the current test helper rotation stuff is currently broken and we have deployed a hotfix, but it's unclear how long it will last for.