Validate the license set during plugin upload

[casiepa]

#4719 enforced setting a license (see also #1944), but is not really checking what is specified as a license.
A check should be made on what the License is set to and the outcome could be:

1. GPL Compatible license
2. GPL Compatible license but not really for software (e.g. for documentation)
3. GPL Incompatible license
4. Unknown license (might be valid but not written in a recognized format)

​https://www.gnu.org/licenses/license-list.html

If option 1., all fine
If option 3., then refuse
If option 2. or 4. check manually

As an example I started those checks in ​https://github.com/ePascalC/CheckPluginForTranslation/

[dd32]

I think we can probably merge this with #1944 in that it's unlikely we'll add a commit check but a pre-upload check instead.

[dd32]

As an example I started those checks in ​https://github.com/ePascalC/CheckPluginForTranslation/

That's a great start!

That would integrate into the process well, there's a two-stage check available here:

• Upload: Accept/Reject (ie. option 3 - Definitely no)
• Review Tooling: Warning on certain things. (ie. Option 2/4 - manual review)

[dd32]

Duplicate of #1944.