Add simplified SPINE script for modern spine-prod configs

[mjkramer]

This adds a new script run_spine.spine-prod.sh that sources spine-prod's configure.sh (so that included yamls are properly found, etc.).

The new script does away with the temp-dir creation / template substitution complexity of the old script, since it is no longer necessary with modern configs.

The interpretation of ND_PRODUCTION_SPINE_CONFIG is simplified: It's just the path relative to run-mlreco; no more magic. So if you want to use a config from spine-prod, it'll look like install/spine-prod/.... If you want to use a config maintained within ND_Production, it'll start with configs/....

Also, this catches up with SPINE's ongoing campaign to replace underscores with hyphens. A symlink from spine-prod to spine_prod is created to ensure backward compatibility.

Addresses #76

TODO:

• Verify that SPINE's output filename mangling scheme is consistent. I have only tested this with one SPINE config so far (the "ND-LAr truth matching" config used in some of the recent samples for charge-readout studies). Confirmed with infer/nd-lar/full_chain_260310.yaml