miniWeather(modernization): build system, directory structure, clang-format, use of most recent YAKL

[janciesko]

This adds the following changes:
Build system

• Treats all external libraries via cmake/modules
• Supports building with YAKL installation
• Adds cmake configure options for all flavors

Example: The following cmake build system invocation is supported.

cmake -DCMAKE_CXX_COMPILER=mpicxx -DPNETCDF_ROOT=$(PNETCDF_INSTALL_PATH) -DYAKL_ROOT=$(YAKL_INSTALL_PATH) DKokkos_ROOT=$(KOKKOS_INSTALL_PATH) -DMW_ENABLE_ALL=On

Directories:

• c -> cpp: Renaming in order to indicate the use of cpp files
• cpp->cpp_yakl: Renaming in order to indicate the use of cpp files and YAKL
• build->scripts: Renaming build directory to scripts in order to avoid confusion

Formatting:

• Adds script to apply clang-format

Code:

• Source files using YAKL were updates to not use the deprecated YAKL API but to use Kokkos instead.

[mrnorman]

Sorry for the delay on this. I'm still not getting notified of PRs even though I'm watching the repo on github. Not sure why yet. Anyway, Luca mentioned this recently, so I'm going to get to this soon. I need to learn a bit more CMake to understand the advantages of install+find_package over add_subdirectory. I've had a lot of problems with find_package failing in the past. Thanks for submitting this!