New versioning method

[kenellorando]

API versioning presently works through arbitrarily setting a value in the cadence.env configuration file and building the container.

This doesn't work when a user clones the repository, runs docker compose up, which could be configured to fetch the latest containers and override their config with whatever is set locally, i.e. whatever they want to set in cadence.env. Ultimately, the version on the display is arbitrary and not tangibly connected the actual content of the code.

Changing this might break 5.0's current version API.