Add container support to repo

[devkelley]

Motivation and Context

Adds support to build and run the service in both docker and podman containers.

Description

This PR does the following:

• Adds a dockerfile to build the container image.
• Adds env file templates to use for docker and podman.
• Updates readme to show how to build and run the service in a container.
• Adds a 'localhost' function that modifies a url to replace 0.0.0.0 with the container's appropriate DNS alias for outbound requests.
• Uses the above 'localhost' function in the pub-sub-service project for all outbound communication (Mosquitto, Chariott, Publisher services)
• Adds a 'containerize' feature to pub-sub-service, putting the DNS replacement code behind it. This feature will be used when building the container from the Dockerfile but is not a default feature.

The following will be addressed in a future PR:

• Update where the yaml configuration files should be placed so that they do not need to be copied from /target/debug when building the container. This should be standardized, and I haven't though enough about where it should go.

[ashbeitz]

Approved

[ladatz]

Just one question, looks good beside that