* Reproducer should decude artifact root from concrete environment
* Add documentation on the layout of the artifacts directory
* Use dag hash in the container name
* Add reproducer options to improve local testing
* --use-local-head allows running reproducer with
the current Spack HEAD commit rather than computing
a commit for the reproducer
* Add test to verify commits and recreating reproduction environment
* Add test for non-merge commit case
* ci reproduce-build: Drop overwrite option
in favor of throwing an error if the working dir is non-empty
1fa1864b37
