[Ekapkgs] Make default license check to be free or "UnfreeRedistributable"

[jonringer]

For software which is unfree, but redistributable, I don't think people should have to "opt in" to this work flow. This may also allow for us to redistribute binaries which are linked against cuda (technically the cuda stubs).

[nrdxp]

Considering almost every NixOS system I have ever built has made use of allowUnfree, I think from a practical standpoint its a good decision, especially since this is somewhat milder.

We aren't going to with the battle for "software freedom" with over-zealous inconvenience, anyway, if the past is any indication...

[ic4-y]

I believe we should rather BAN all talk about unfree software and make all ways to circumvent restrictions against unfree software impracticable, dare I say: unthinkable. Maybe we could tell Nvidia users to switch to AMD instead? And I believe PyTorch has a Vulkan backend? There appears to be no excuse left for proprietary software.

We should ensure that things like nonguix cannot even be conceived of in our case.

So yes, it does sound like a reasonable idea.