Build automation for generating the dev container

[brooke-hamilton]

Benefit/Result/Outcome
Need an up-to-date build of the dev container in a container repo, so that it can be used for build automation.

Description
The dev container defined in the .devcontainer folder is used for build automation as well as day-to-day development. Developers normally build the container locally from the Dockerfile in that folder, but the build system using GitHub Actions needs a pre-built container for running build automation.

Acceptance Criteria

• An automated container build runs either on a schedule or upon changes to the to the Dockerfile.

[brooke-hamilton]

Closing as no longer a priority.