Add model-validation-operator to Pulumi

[haydentherapper]

Description

https://github.com/sigstore/model-validation-operator was transferred into the org, we need to set up the Pulumi configs for it.

FYI @cpanato @miyunari

[haydentherapper]

@cpanato Did you have instructions on how to import a project into Pulumi? I'm happy to do it, just wanted to check before breaking anything. Is it just https://www.pulumi.com/docs/iac/cli/commands/pulumi_import/?

[cpanato]

sorry missed this :(