add content_rating to metainfo and fix metadata_license

[christianrauch]

This adds the tag content_rating to the metainfo.xml using the interactive form at https://odrs.gnome.org/oars.

The metadata_license states GPL-3.0 AND Apache-2.0. I assume this only applies to the project and not the metadata, i.e. this metainfo.xml itself. Usually, these metadata files use one of the "Creative Commons" licences. I propose to use the "CC0-1.0".

[booo]

Cloud you please describe which metadata we are talking about? And maybe add a link to the metainfo.xml documentation?

I guess it is fine to merge but I will wait for the feedback first.

[christianrauch]

Cloud you please describe which metadata we are talking about?

Well, I mean the only file that is changed by this PR (deploy/org.mavlink.qgroundcontrol.metainfo.xml) of course.

And maybe add a link to the metainfo.xml documentation?

The file is standardised: https://freedesktop.org/software/appstream/docs/chap-Quickstart.html

[booo]

Thanks a lot for the clarification.

I personally think the change is fine. I'm new to licenses changes and a bit unsure how to deal with this in a proper way even if it only concerns one stupid metadata file. Do we have to ask the right holders?

[christianrauch]

Do we have to ask the right holders?

Someone has to agree to change the licence of this single xml metadata file. Not sure how this is handled internally, but I assume that whoever has the right to merge PRs can decide this. Looking at the history of that file I can see that only @thopiekar committed to that file, starting in 2021.

[booo]

Thanks again for the explanation!

I will merge this now. The potential right holder had two weeks to respond to the issue. I think that's enough.