c-blosc needs a CMake package file

[bnavigator]

@thewtex suggests to create a CMake package file instead of this PRs FindBlosc.cmake

Yes, we should definitely be using a CMake package configuration file instead of a Find module. But, if @bnavigator is not willing to make those changes, this is still a step forward. We could merge this and make additional progress later.

Originally posted by @thewtex in Blosc/python-blosc#244 (comment)

[mgorny]

Gentle ping. Apparently python-blosc already requires this file even though FWICS nobody wrote it x_x.

[bnavigator]

python-blosc does not require this file. It provides it's own FindBlosc.cmake because the CMake package file does not exist yet.

[imikejackson]

Gentle ping on this? Or maybe I'm just not trying to include C-Blosc in the correct way in my project? Should I just use a git-submodule instead and build blosc as part of my project?