Remove the need to specify ENVIRONMENT and deploy only based on git diff

This issue (https://github.com/bitovi/bitops/issues/32) added the ability to only deploy an environment if `$ENVIRONMENT` matches changed files in the `git diff`.

@ConnorGraham brought up an advanced version of this:
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Slightly different context, but this should be expanded to do more than selectively deploy Helm charts. It should also select the whole ops repo `ENVIRONMENT`, if not provided

Instead of providing the `ENVIRONMENT` env var on every BitOps run, it would be nice if there was an auto or git mode that would auto-detect what environment to run based on what has changed in the latest commit to the ops repo