Add SimulateCavern simFlag, which can be used independently of CavernBG and cosmics simulation

As reported in ATLASSIM-4216, for radiation studies it is useful to be able to include the ATLAS Cavern in simulations without making the other configuration tweaks associated with Cosmic-ray and Cavern Background simulation. This merge request adds a SimulateCavern simFlag which is set when running Cosmic-ray and Cavern Background simulation jobs, but can also be set separately to allow the cavern to be included in simulations with no other changes.

added 21.0 label

FYI @menke

This merge request affects 5 packages:

• Simulation/G4Atlas/G4AtlasApps
• Simulation/G4Atlas/G4AtlasServices
• Simulation/G4Atlas/G4AtlasTools
• Simulation/ISF/ISF_Config
• Simulation/ISF/ISF_Geant4/ISF_Geant4Tools

Adding @jchapman ,@vpascuzz as watchers

added Simulation review-pending-level-1 labels

CI Result SUCCESS

	Athena	AthDataQuality	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-25081-2019-07-24-15-16
Athena: number of compilation errors 0, warnings 0
AthDataQuality: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST 40052]

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 3c6ad775

added sweep:done label

mentioned in commit 74afcd92

mentioned in merge request !25110 (merged)

Sweep summary
successful:

• master

(see https://aiatlas154.cern.ch/jenkins/job/auto_git_sweeps/855/console for details)

mentioned in commit 612d0c4c

mentioned in merge request !25152 (merged)

mentioned in merge request !25152 (merged)

mentioned in commit 6092b5bd