This PR improves statistics reporting for MGR.
A list with detailed changes is given below:
* Add MatrixStats and MatrixStatsArray
* Add hypre_squared utility
* Fix divisor line location for Rectangular matrices
* Minor fix on hypre_squared definition
* Move nonzero variable definitions up
* Initialize global number of nonzeros at matrix creation
* Add hypre_ParCSRMatrixStatsArray and helper functions
* Add par_csr_matstats_device
* Add par_mgr_stats
* Print F-relax data only once
* Fix clang-13 build
* IJ driver now passes in print_level option to MGR
* GPU runs always require A_FF in MGR
* Add HYPRE_PRINT_SHIFTED_PARAM macro
* Add hypre_IntArraySetInterleavedValues (host/device implementations)
* Fix F-relaxation reporting + refactoring
* Update global number of nonzeros of the matrix
* Move new BoomerAMG functions to par_stats
* Apply astyle
