Git versioning for basic version control

[ThierryCantin-Demers]

Do not permit user to upload code if git has uncommited files.
Check git commit hash to check if code should be uploaded, should only upload if git commit hash has changed.

Change the cli to have the following args instead of local and remote runs:

• --runner <runner-group>: if specified, run on specified runner. Otherwie run locally
• --version <code-version>: if --runner is present, tell runner which code version to run. Otherwise, git checkout the specified git commit hash and run this version.