Feat: ask the school about getting back our copyrights to apply a Free software license

[samuelroland]

I'm going to start this process next week, I hope.

• Write to EBX to know how it works and who should I contact
• Write to the responsible person
• Think about and choose a license, ask the group about this decision
• Change Cargo.toml license field to valid SPDX
• Think about the DCO (see example for Forgejo)
• Open a PR including the licence, a copyright notice in the README, remove current license section text in README, add the notice required by the school
• Get everyone's approvals, before merging
• Adapt website to mention the license