Update gitlab package to expose common helm path override variables that are currently being copy/pasted across uds-bundle.yaml files

[zachariahmiller]

Is your feature request related to a problem? Please describe.

update gitlab package to use the variable override definitions in zarf that have been used via bundle overrides to date so that there is less copy/paste of common variable overrides into bundles definitions

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defenseunicorns/zarf#2403
defenseunicorns/zarf#2133

[zachariahmiller]

Follow up tickets to do this for the other packages as well.