Add perses-operator libsonnet

[saswatamcode]

This commit adds a jsonnet lib to perses operator, so that the CRDs and definitions can be imported by downstream stacks like kube-prometheus

[saswatamcode]

cc: @simonpasquier

[simonpasquier]

Shouldn't we convert the perses*-crd.json from config/crd/bases using gojsontoyaml?

[saswatamcode]

@simonpasquier ok I kind of tried a trick here. I basically converted all the kubebuilder generated YAML to json in jsonnet dir, then import and modify those.

So any future edits of the original kubebuilder YAML would reflect into the jsonnet lib.

Let me know if this seems reasonable, cc: @jgbernalp

[simonpasquier]

Should we highlight generated files more prominently? Either .json files go to jsonnet/enerated/ or we add some header to the json files?
Also I'm not sure that we need to keep the manifests generated from jsonnet in the repository since they kinda overlap with the manifest files.
One last thing: it would be good to run jsonnetfmt on the json/jsonnet files.

[saswatamcode]

@simonpasquier I added fmt and linting for jsonnet.
I'm also storing all the generated json in a generated dir.

As for the manifests generated by jsonnet, I would still like to keep them, as you can test those manifests on a cluster and validate that things work as expected.

[simonpasquier]

LGTM