Outputs ns for gateways in gwctl

[xtineskim]

What type of PR is this?

What this PR does / why we need it:
Related to small usability for gwctl.
Now the following output for gwctl get gateways -A

NAMESPACE  NAME    CLASS   ADDRESSES       PORTS  PROGRAMMED  AGE
cilium     cilium  cilium  172.18.255.200  80     True        2h
default    cilium  cilium  172.18.255.201  80     True        2h

Which issue(s) this PR fixes:
Related to #3133

Fixes #

Does this PR introduce a user-facing change?:

NONE

[k8s-ci-robot]

Hi @xtineskim. Thanks for your PR.

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[gauravkghildiyal]

Thanks @xtineskim!. This LGTM

/ok-to-test
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gauravkghildiyal, xtineskim

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