Revert "Revert "Add CC-BY-NC-SA-license file""

This reverts commit 1abb83bc9449a0df25f71663c781b5f7acb8074f.
Revert "Revert "Revert "Add CC-BY-NC-SA-license file"""

This reverts commit dd8c4b47787e45c276952dc7b10697e5ac47d6c9.