FindLapack, FindScalapack improvments

Simplify MKL finding

factory FindMPI

v2.1.0.26

FindMPI: use factory

further enhance FindMPI robustness across platforms

v2.1.0.25

FindMPI more robust

Enhanced FindMPI

increase reliability of FIndMPI

lapack 3.10.0, improved FindMPI

v2.1.0.23

build lapack: work for CMake < 3.20

BUGFIX missing files, FindMPI improved, Clang compatibility

• BUGFIX: fixed missing source files, that was broken by v2.1.0.21
• check and set flag -Wnoimplicit-function-declarations as Clang errors otherwise, and GCC emits lots of warnings otherwise
• improved FindMPI with our own written from scratch--works better on MacOS and CentOS in particular and doesn't bother with ancient/obscure MPI implementations

correct missing source file, new build approach

Instead of Git tracking the original sourc,e, we extract the source tarball and inject our CMake for better tracability

use lapack 3.9.1

if lapack not found, build lapack v3.9.1

Improve packaging

• modernize CMake per other projects
• add find_dependency to auto find deps

improve packaging

improve example to use new packaging efficiently