feat(nginx): replace docker.io nginx with Red Hat hardened image

[vbelouso]

Closes APPENG-5492

Migration to Red Hat supported container images required by security policy compliance.

The upstream nginx approach for environment variable substitution in config templates (https://hub.docker.com/_/nginx#using-environment-variables-in-nginx-configuration-new-in-119) cant be used directly because Red Hat supported nginx container images dont provide this functionality.

The test environment is available in ns daboogie-eiq

[vbelouso]

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