Add EUPL-1.2 to licenses list

[AsbjornOlling]

Just adding another license.

I took the short and long names from SPDX

I was unsure of where to add it in the list, since putting it at the end next to proprietary licenses doesn't feel right. I ended up putting it right after the other copyleft software licenses, since EUPL is also a software-focused copyleft license, and since it is explicitly compatible with the GNU copyleft licenses.

I hope that makes sense.

[Calinou]

Is there any project you plan to upload to the asset library that uses this license? I'd prefer not making the list too long if no project plans to use this license.

[AsbjornOlling]

@Calinou I'm plannign to use it with my EUPL-1.2 licensed project "Nobody Who"

Currently I have "LGPL" on the asset library page, since that's the most similar compatible license.

Source code here: https://gitlab.com/nobodywho/nobody Godot asset library page: https://godotengine.org/asset-library/asset/2886

[AsbjornOlling]

@Calinou is my project sufficient?

[coppolaemilio]

After chatting with the user I think we should add the license, but in the future I think it might be better to have a text-field instead of a dropdown for this 😅