Choosing a licence for the site

[mxochicale]

There are various examples for licences that we can use:

• https://github.com/Qiskit/qiskit.org/blob/master/LICENSE.txt
• https://github.com/arduino/Arduino/blob/master/license.txt https://www.gnu.org/licenses/gpl-3.0.en.html
• https://github.com/ubuntu/yaru/blob/master/LICENSE_CCBYSA https://creativecommons.org/licenses/by-sa/4.0/
• https://github.com/pytorch/pytorch/blob/master/LICENSE

I guess we have to choose the one that aligns better with the spirit of the open-source community.