Update SDC schemes for PFASST algorithm.

Issue/feature addressed

This is a redesign of the SDC scheme algorithm in prevision for the PFASST algorithm integration. In addition, Chebyshev quadrature have been removed but Gauss Legendre quadrature have been added to the SDC schemes and size_t is now used instead of int or unsigned int when appropriate. Finally, the offset parameter has been eliminated in the integration matrix computation in Polylib.cpp.

Tests

The following test have been added to the CI

TimeIntegrationDemoSDCExplicitGaussGaussLegendreOrder2.tst
TimeIntegrationDemoSDCExplicitGaussGaussLegendreOrder4.tst
TimeIntegrationDemoSDCExplicitGaussGaussLegendreOrder6.tst
TimeIntegrationDemoSDCExplicitGaussGaussLegendreOrder8.tst
TimeIntegrationDemoSDCImplicitGaussGaussLegendreOrder2.tst
TimeIntegrationDemoSDCImplicitGaussGaussLegendreOrder4.tst
TimeIntegrationDemoSDCImplicitGaussGaussLegendreOrder6.tst
TimeIntegrationDemoSDCImplicitGaussGaussLegendreOrder8.tst

Suggested reviewers

Please suggest any people who would be appropriate to review your code.

Notes

Please add any other information that could be useful for reviewers.

Checklist

• Functions and classes, or changes to them, are documented.
• [ ] User guide/documentation is updated.
• Changelog is updated.
• [ ] Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• [ ] License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).