Add REUSE Software compliance check

[Ludee]

Summary of the discussion

We make licensing easy for humans and machines alike. We solve a fundamental issue that Free Software licensing has at the very source: what license is a file licensed under, and who owns the copyright?

    Choose and provide licenses
    Add copyright and licensing information to each file
    Confirm REUSE compliance

https://reuse.software/

Type of change (CHANGELOG.md)

Added

• Add REUSE Software compliance check (#218)

Workflow checklist

Automation

Closes #211

PR-Assignee

• 🐙 Follow the workflow in CONTRIBUTING.md
• 📝 Update the CHANGELOG.md
• 📙 Update the documentation
• 🐙 Assign a reviewer to the PR

Reviewer

• 🐙 Follow the Reviewer Guidelines
• 🐙 Provided feedback and show sufficient appreciation for the work done

[Ludee]

[jh-RLI]

Looks very good. Establishing this will end any expert discussion on tracking the licenses used in detail :) Very nice that you added the automated check.

I think in general we could be a bit more generous when adding the copyright holder as this seems to indicate whom was part of the contribution to the files but i personally do not care enough about this detail :) good that there is a holder in every files making the Repo compliant.

[jh-RLI]

this file can be removed as we do not use the travis ci anymore. We use GitHub Actions.