log_vc_info: expose output via Jinja2 plugin

[oliver-sanders]

Consider exposing the data captured by the log_vc_info plugin to the workflow configuration via a Jinja2 plugin.

Also consider expanding the range of information captured within reason.

This is to enable the extraction of VC metadata (e.g, things like branch names and commit hashes) which may have utility within the workflow.

Adding the investigation label for now as the use cases and required metadata are not quite understood.