Squashed 'external/ViennaMath/' content from commit fb470c0

git-subtree-dir: external/ViennaMath
git-subtree-split: fb470c0660c7ee068b596955d47e9643f75267e3
Merge commit 'ae54035d413e45ff6d5ab2cf89b0a93e35145cb2' as 'external/ViennaMath'
some dubious changes in ViennaMath::benchmark-utils.hpp after subtreeing ViennaMath
changed gitattributes for now: I think it introduces some headache with subtree
Squashed 'external/ViennaFVM/' content from commit 70e6570

git-subtree-dir: external/ViennaFVM
git-subtree-split: 70e65700b7e94c48b47f5cf63aa86ca1ab1b4b5b
Merge commit '81c07f84381eb222d72a6d26f70b2e7276ec0cba' as 'external/ViennaFVM'
ViennaMini updates due to ViennaData accessor api changes + fixed INI mesh file paths