Allow users to configure OTel parameters for their excecutor

[calebschoepp]

Users need to be able to set OTel parameters like OTEL_EXPORTER_OTLP_ENDPOINT on their chosen executor to enable o11y.

[calebschoepp]

Relevant design work is being tracked here.

[calebschoepp]

Talking through this with Michelle we decided it makes sense to define OTEL parameters on the SpinAppExecutor, but that it probably makes sense to hold off on defining OTEL parameters on the SpinApp (not all executors would be able to support setting it at the app level and we also don't want to pull too many infra concerns into the app CR). We also think that the OTEL values should be scoped under the deployment config since they only work for sure with the shim executor.

We'll allow list the OTEL values in the operator so that arbitrary environment variables can't be injected. Here's an example of the schema.

apiVersion: [core.spinoperator.dev/v1alpha1](http://core.spinoperator.dev/v1alpha1)
kind: SpinAppExecutor
metadata:
  name: containerd-shim-spin
spec:
  createDeployment: true
  deploymentConfig:
    runtimeClassName: wasmtime-spin-v2
    installDefaultCACerts: true
    otel: map[string, string]

[calebschoepp]

#273 is related.

[calebschoepp]

@asteurer is working on this

[calebschoepp]

Closed by #273