Updates for Full NDLAr During Fresh Pass (Round 2)

[alexbooth92]

Similar to PR #52, some minor but important updates related to the full ND geometry workflow.

Everything here should be completely transparent for 2x2. Potentially influential for 2x2 are the changes in validation scripts for larnd-sim and flow where they have been made IO group and IO channel agnostic. I have tested that all original behaviour is retained using 2x2 input. Proof of that can be found in the files MiniRun*.pdf in docdb-31528. There is also one more plot in the edepsim level validation script.

Other changes / additions:

• The USE_GHEP_POT feature for hadding and spill building requires an executable to be built. I have now added an install script consistent with those in other packages and made the necessary additions to the install_everything.
• Related to this, a PR I made some time ago allowing fiducial only or rock only spill building broke the USE_GHEP_POT feature, have now fixed the spill building run script.
• Paired with PR 107 in the ndlar_flow package, add a few lines using a "getting" script to the flow install script.
• Added a full NDLAr flow workflow run_ script.