Deprecate build-related content in Serverless CRD

[kwiatekus]

Description:
We are proposing to deprecate the following fields from the Serverless Custom Resource Definition (CRD) and clean up the status spec from all build and docker-registry related content:

• spec.dockerRegistry
• spec.targetCPUUtilizationPercentage
• spec.functionBuildExecutorArgs
• spec.functionBuildMaxSimultaneousJobs
• spec.defaultBuildJobPreset

Deprecate all related status fields as well.
This fields are no longer relevant to the current architecture and will be marked for deprecation.

AC:

• Build related content (from spec and status )is are marked as deprecated.
• Documentation is updated to reflect the deprecations and removals.

Reason:
As part of the efforts towards build-less serverless we are simplifying the Serverless CRD and deprecating fields that we see unnecessary in the future. The cleanup of the status, spec and conditions will help avoid confusion and improve the maintainability of Serverless.