Speed up common CertifyVuln ent queries by adding indexes

[nchelluri]

Description of the PR

In our use of GUAC with the ent backend, we were noticing some high DB load from some CertifyVuln queries. This PR should help with that.

I also added a PR checklist item for next time:

• If ent schema is changed, make generate has been run

PR Checklist

• All commits have a Developer Certificate of Origin (DCO) -- they are generated using -s flag to git commit.
• All new changes are covered by tests
• If GraphQL schema is changed, make generate has been run
• If GraphQL schema is changed, GraphQL client updates/additions have been made
• If OpenAPI spec is changed, make generate has been run
• If collectsub protobuf has been changed, make proto has been run
• All CI checks are passing (tests and formatting)
• All dependent PRs have already been merged

[pxp928]

Awesome! Thanks!

[mrizzi]

@nchelluri thanks!