PetSC source compilation and CMake detection

[abhinavsns]

Currently, OpenFPM uses find_package(PETSc) for PETSc detection, this is not ideal because the corresponding CMake module findPETSc.cmake is deprecated.
Further, a lot of options in script/install_PETSC.sh are no longer used.

A potential solution is to move to pkg-config. This is recommended by petsc-dev: https://www.mail-archive.com/[email protected]/msg28259.html

Example implementation using pkg-config can be found at: https://stackoverflow.com/a/67885007

[abhinavsns]

With petsc 3.20.5 on MacOS arm64, I noticed a workaround can be to add METIS/lib to the ld_lib_pathopt in script/conf_CMake.sh just like we do for SUITESPARSE.

openfpm/script/conf_CMake.sh

Line 156 in 2043936

ld_lib_pathopt=$prefix_dependencies/SUITESPARSE/lib

[abhinavsns]

Now with the new config process that removes config.h, I noticed the HAVE PETSC variable is written correctly for abuild with $make but not for the binaries headers when installed using $make install on my macbook pro arm64.

Also the github Ubuntu CI is failing to detect PetSC and Eigen both.
@syaskovets
@incardon