* ENH: add catch2 CMake install
* add a variant allowing catch2 to be installed
via CMake, which is useful for generating a .cmake
config file for consumption by other projects
* Catch2: Simplify Package
- CMake install is also single-header for new releases
- testing triggered by Spack's test mechanism
- default to CMake build (better than simple copy, which is
just for old releases to be installed)
* Catch: Remove Variant
We can control all installs with CMake to be quick and complete.
Old versions prior to 1.7.0 will be manually installed, as the
`make install` target is missing in those.
Releases 1.7.0-1.9.3 do not expose control over test builds.
* openPMD-api: Catch Lost single_header
... variant is gone :)
Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>
