Change error messages from namespace to gateway

[Elson9]

Description

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Documentation (non-breaking change with enhancements to documentation)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have checked that unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[rustyjux]

Seems good though I'm not sure what sort of testing (if any) is in place for this repo.
Also Docker Image for gwa-kube-api failed:

#2 ERROR: failed to copy: httpReadSeeker: failed open: unexpected status code https://registry-1.docker.io/v2/library/python/manifests/sha256:ef097620baf1272e38264207003b0982285da3236a20ed829bf6bbf1e85fe3cb: 429 Too Many Requests - Server message: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit

From Docker website, the limits are:

Anonymous and Free Docker Hub users are limited to 100 and 200 container image pull requests per six hours.

Hopefully that doesn't prevent a release