add default values to operatorconfiguration crd

[FxKu]

since v1 and K8s 1.17 allows defining defaults in the CRD schema validation. With this we could at some point get gid of all the coalescing in operator_config.go.

For compatibility with older K8s versions a coalesce function for int64 is added. The go code for the CRD validation does not use defaults at the moment because values have to be defined as *JSON (which looks like too much work right now - and maybe we drop this code at some point anyway to only rely on manifests).

This PR incl. a few more minor changes:

• adding logical_backup_job_prefix to CRD validation and all examples
• adding v1.6.0 tag to every mention of the logical backup image
• adding master-12 tag to default pooler image
• setting minimum of connection_pooler_number_of_instances to 1

addresses #1277

[zalando-robot]

Docker image "registry-write.opensource.zalan.do/acid/postgres-operator-ui-test:v1.6.0-12-g78a92bd-pr-1283-4" is not based on an approved base image. Currently, this will have no impact on your deployments, but builds using non-allowed images will be blocked from deployment from February 1st 2021.

To create a compliant Docker image of your application, you must reference an allowed Docker image as its base image in your Dockerfile. This base image must come from the Open Source Registry namespace library and use a recommended version as listed in the documentation.

[zalando-robot]

Docker image "registry-write.opensource.zalan.do/acid/postgres-operator-ui-test:v1.6.0-15-g93a8230-pr-1283-5" is not based on an approved base image. Currently, this will have no impact on your deployments, but builds using non-allowed images will be blocked from deployment from February 1st 2021.

To create a compliant Docker image of your application, you must reference an allowed Docker image as its base image in your Dockerfile. This base image must come from the Open Source Registry namespace library and use a recommended version as listed in the documentation.

[FxKu]

👍

[sdudoladov]

👍