Pick a license, add license stuff and reuse linter

[avnik]

Before opening, project need a license

[aciceri]

Ooops, it's already public. Just asked internally which license we should use. Will update the repo as soon as possible.

[aciceri]

I believe MIT should be fine.

[avnik]

we agreed about "Apache-2.0", I add license stuff as well as license linter to "flake check" sequence

[aciceri]

Yeah feel free to add the license. I'm not sure to understand what you mean by license linter instead.
In mlabs-haskell/spo-anywhere I simply added this file. If it could be done better in your opinion then please fix it also there.

[avnik]

Closed by #15