Add the imagePullPolicy attribute to the CR

[mimatache]

Currently the operator does not support setting the imagePullPolicy on the spec.

I would like to be able to set this policy, especially for development helping purposes, sice it would allow anyone developing their own custom collector to test it/demo it with the operator without actually having to push it to an image repository.

I am offering to add this functionality if it is desired.

[jpkrohling]

If the image is available in the same cluster, you can use the digest format, like quay.io/opentelemetry/opentelemetry-operator@sha256:c08f811f3db58ddaf4aa26e49fb235ba4fa1f1909659e995a3275795801a44a8.

I'm OK in having this feature though. Feel free to send a PR for it.

[mimatache]

I would love to do the PR. Are there any special versions of kustomize or operator-sdk or any other dependencies I need to use? Or something special I need to do?
I get the following issue running make bundle as stated in the CONTRIBUTING.md:

 > make bundle
/home/mihai/golang/go/bin/controller-gen "crd:trivialVersions=true,preserveUnknownFields=false,generateEmbeddedObjectMeta=true" rbac:roleName=manager-role webhook paths="./..." output:crd:artifacts:config=config/crd/bases
/usr/local/bin/operator-sdk generate kustomize manifests -q
WARN[0000] Skipping definitions parsing for API {}: Go type not found 
/usr/bin/kustomize build config/manifests | /usr/local/bin/operator-sdk generate bundle -q --overwrite --manifests --version "0.33.0-3-g4621407"  
/usr/local/bin/operator-sdk bundle validate ./bundle
ERRO[0000] Error: Value opentelemetry-operator-controller-manager: invalid service account found in bundle. sa name cannot match service account defined for deployment spec in CSV 
make: *** [Makefile:219: bundle] Error 1