fix: make new gravity treatment from #3337 an option

[paveltomin]

disabled by default since SPE11 case degradations were observed

[victorapm]

This PR matches with the reference results for spe11b. Thanks!

[paveltomin]

@CusiniM and @ryar9534 let's please move this fix quickly into develop, critical for spe11

[CusiniM]

I don' t know that we really need 2 options for the treatment of gravity. In general, I think that what @paveltomin had introduced made more sense... I am not too sure why it would have such a large impact on convergence.

[codecov]

Codecov Report

Attention: Patch coverage is 43.18182% with 50 lines in your changes missing coverage. Please review.

Project coverage is 57.11%. Comparing base (b56762c) to head (705fef5).
Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
...vers/fluidFlow/kernels/compositional/CFLKernel.cpp	0.00%	28 Missing ⚠️
...s/fluidFlow/kernels/compositional/IHUPhaseFlux.hpp	0.00%	16 Missing ⚠️
...idFlow/kernels/compositional/FluxComputeKernel.hpp	50.00%	3 Missing ⚠️
...sSolvers/fluidFlow/CompositionalMultiphaseBase.cpp	85.71%	1 Missing ⚠️
...fluidFlow/kernels/compositional/C1PPUPhaseFlux.hpp	0.00%	1 Missing ⚠️
...olvers/fluidFlow/kernels/compositional/PotGrad.hpp	96.15%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3467      +/-   ##
===========================================
- Coverage    57.11%   57.11%   -0.01%     
===========================================
  Files         1151     1151              
  Lines        99454    99475      +21     
===========================================
+ Hits         56808    56818      +10     
- Misses       42646    42657      +11     

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[rrsettgast]

@paveltomin The term newGravity is quite uninformative. Can you create descriptive options for the "gravity treatment" so that developers/users know what the treatments are?

[paveltomin]

@paveltomin The term newGravity is quite uninformative. Can you create descriptive options for the "gravity treatment" so that developers/users know what the treatments are?

Ok will do

[paveltomin]

@paveltomin The term newGravity is quite uninformative. Can you create descriptive options for the "gravity treatment" so that developers/users know what the treatments are?

is this #3486 better?