Add replacements for manifests

[Griffin-Sullivan]

Is your feature request related to a problem? Please describe. A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] It is difficult to deploy multiple model registries in a cluster, as there are some names that need to change in the manifest files for services and deployments.

Describe the solution you'd like A clear and concise description of what you want to happen. Use a replacements file to make it more straightforward how we expect upstream users to deploy multiple model registries in a cluster.

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered. Open to anything that makes multi-MR easier to set up.

Additional context Add any other context or screenshots about the feature request here.

[Griffin-Sullivan]

@dhirajsb feel free to edit this to be more accurate since I'm not super familiar with the solution here