Update cmake configuration files for PETSc according to the code review

CMakeLists.txt

MathLib/CMakeLists.txt

Tests/CMakeLists.txt

scripts/cmake/ExternalProjectBoost.cmake

scripts/cmake/Find.cmake

scripts/cmake/SubmoduleCheck.sh

scripts/cmake/findPETSC/FindPETSc.cmake

scripts/cmake/findPETSC/FindPackageHandleStandardArgs.cmake

scripts/cmake/findPETSC/FindPackageMultipass.cmake

scripts/cmake/findPETSC/LICENSE

scripts/cmake/findPETSC/README.txt

scripts/cmake/findPETSC/ResolveCompilerPaths.cmake

scripts/init.sh

scripts/setup/setup.sh

scripts/setup/setup_libraries.sh

scripts/setup/setup_prerequisites.sh

scripts/test/gcovr