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 : $dx = \displaystyle \frac{-3V{max}}{2L}log(R)(\frac{x}{L})^2$ 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

Attention: Patch coverage is 63.92405% with 57 lines in your changes missing coverage. Please review.

Project coverage is 56.60%. Comparing base (41e95e3) to head (d2752ab).

Files with missing lines	Patch %	Lines
...econdOrderEqn/isotropic/ElasticWaveEquationSEM.cpp	20.83%	19 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:
...sicsSolvers/wavePropagation/shared/TaperKernel.hpp	65.21%	8 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #3224 +/- ## =========================================== + Coverage 56.59% 56.60% +0.01% =========================================== Files 1064 1066 +2 Lines 89762 89920 +158 =========================================== + Hits 50802 50903 +101 - Misses 38960 39017 +57 ```

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