feat: add file module

[TECHNOFAB11]

This makes it possible to "import" yaml files. Kinda like a basic Kustomization but without needing any CLI/tool. Reused a lot of stuff from the Helm module, so it works fundamentally the same

[adrian-gierakowski]

There is already a facility for this

see here

https://github.com/hall/kubenix/blob/76b8053b27b062b11f0c9b495050cc55606ac9dc/modules/k8s.nix#L345

And here

https://github.com/hall/kubenix/blob/76b8053b27b062b11f0c9b495050cc55606ac9dc/modules/k8s.nix#L517

i think it doesn’t handle multi-doc yaml file so if you need it maybe just improve the existing functionality?

[TECHNOFAB11]

I'd actually prefer the approach of having multiple "keys" like I implemented it. This way it works more like Kustomize and one can specify an override per file (for setting the namespace for every object for example).

Sorry for not responding faster.