Add a license

From a discussion with @bneron the AGPL might be the one. Need further discussion.

ping @echapeau

added documentation label

mentioned in commit 8e3e2459

mentioned in merge request !242 (merged)

# add lice to easily generate the license
pip install lice

# Add license
lice agpl3 -o "The STRASS Authors" -p STRASS > LICENSE
git add LICENSE

cd src/strass
# generate license header
lice agpl3 --header -o "The STRASS Authors" -p STRASS > header.txt
# add it in every python file
docker run -it -v ${PWD}:/src ghcr.io/google/addlicense  -c "The STRASS Authors" -f /src/header.txt **/*.py **/**/**/*.py **/**/*.py

mentioned in commit 32b068c4

closed with merge request !242 (merged)