Remove graphqlbackend dependency from codemonitors stores

Created by: camdencheek

This commit establishes a clean separation between the graphqlbackend layer and the database layer for code monitors. Previously, the code monitor store imported and reused types from graphqlbackend. This creates types specific to the store, and converts to those types before calling the store.

This is necessary in order to move the store wrapper into a shared database package. We don't want to make graphqlbackend a transient dependency on every package that imports the database package.

This PR isn't as bad as it looks. It's basically just taking the graphqlbackend types, replacing them with package-local types, then doing the graphql-specific conversion in the graphqlbackend package.