feat: Add Taper Layers in wave solvers

[acitrain]

This PR add a first version of Taper layers for wave solvers These layers are set to improve the efficiency of absoption of boundaries. This is how the version version works:

• We compute a taper profile which is equal to one when you are outside the taper layers and to : $d_x = \displaystyle \frac{-3V_{max}}{2L}log(R)(\frac{x}{L})^2$ where $V_{max}$ is the maximum P-wavespeed, L the length of the taper layer and R the reflectivitity coeff (which is between $10^{-3}$ and $10^{-6}$
• Then we multiply by the array at time n and n+1 by the taperCoeff

For this first version only second order solver contains the taper functionality and the computation of the profile as been simplified in particular in corner cases.

Those two functionalities will be add in a next PR.

[codecov[bot]]

Codecov Report

:x: Patch coverage is 73.97260% with 57 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 58.45%. Comparing base (0cb3f1f) to head (f3c9761). :warning: Report is 94 commits behind head on develop.

Files with missing lines	Patch %	Lines
...econdOrderEqn/isotropic/ElasticWaveEquationSEM.cpp	39.47%	23 Missing :warning:
...qn/isotropic/AcousticFirstOrderWaveEquationSEM.cpp	0.00%	10 Missing :warning:
...rderEqn/anisotropic/AcousticVTIWaveEquationSEM.cpp	0.00%	10 Missing :warning:
...Eqn/isotropic/ElasticFirstOrderWaveEquationSEM.cpp	0.00%	10 Missing :warning:
...condOrderEqn/isotropic/AcousticWaveEquationSEM.cpp	88.23%	4 Missing :warning:

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3224      +/-   ##
===========================================
+ Coverage    58.42%   58.45%   +0.03%     
===========================================
  Files         1270     1272       +2     
  Lines       109177   109385     +208     
===========================================
+ Hits         63786    63941     +155     
- Misses       45391    45444      +53     

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[acitrain]

Hi @rrsettgast

Could you take a look at it and approve if it seems good to you? It is ready except integrated test but I want to do it after a code owner review

Thank you !

PS: I don't know why the docs build does not pass, it is only saying "We encountered a problem with a command while building your project. To resolve this error, double check your project configuration and installed dependencies are correct and have not changed recently."

[acitrain]

@sframba @rrsettgast @CusiniM can you review this please ?

Thanks

[acitrain]

@rrsettgast @CusiniM can one of you take a look to this? It is ok on our side we just need a code owner review to go to the merge queue and do integrated test when this PR will be at the top

Thanks !