[MatL] Add explicit template instantiation declarations.

Some fixes for conda build.

When building MaterialLib dynamically there are still undefined symbols at runtime:

$ objdump -t -C ~/.conda/envs/ogs-test/lib/libMaterialLib.so | ag ' . .*formKelvinVector

[NOTHING]

$ objdump -t -C ~/.conda/envs/ogs-test/lib/libThermoHydroMechanics.so | ag ' . .*formKelvinVector'
0000000000000000         *UND*    0000000000000000              Eigen::Matrix<double, MathLib::KelvinVector::kelvin_vector_dimensions(3), 1, 0, MathLib::KelvinVector::kelvin_vector_dimensions(3), 1> MaterialPropertyLib::formKelvinVector<3>(std::variant<double, Eigen::Matrix<double, 2, 1, 0, 2, 1>, Eigen::Matrix<double, 3, 1, 0, 3, 1>, Eigen::Matrix<double, 2, 2, 0, 2, 2>, Eigen::Matrix<double, 3, 3, 0, 3, 3>, Eigen::Matrix<double, 4, 1, 0, 4, 1>, Eigen::Matrix<double, 6, 1, 0, 6, 1>, Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&)
0000000000000000         *UND*    0000000000000000              Eigen::Matrix<double, MathLib::KelvinVector::kelvin_vector_dimensions(2), 1, 0, MathLib::KelvinVector::kelvin_vector_dimensions(2), 1> MaterialPropertyLib::formKelvinVector<2>(std::variant<double, Eigen::Matrix<double, 2, 1, 0, 2, 1>, Eigen::Matrix<double, 3, 1, 0, 3, 1>, Eigen::Matrix<double, 2, 2, 0, 2, 2>, Eigen::Matrix<double, 3, 3, 0, 3, 3>, Eigen::Matrix<double, 4, 1, 0, 4, 1>, Eigen::Matrix<double, 6, 1, 0, 6, 1>, Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&)

Therefore building it statically on Conda builds.

Related: https://github.com/conda-forge/staged-recipes/pull/26704

changed the description

approved this merge request

changed milestone to %6.5.4

enabled an automatic merge when all merge checks for ea93ab7a pass

canceled the automatic merge

mentioned in commit 01b17f73

merged