Switch from using Nais API GraphQL to Nais API GRPC

[thokra-nav]

Today, Bifrost and Unleash uses the Graphql API to list teams etc. This requires the use of static service accounts managed by Terraform and are now deprecated.
We have an internal API using GRPC that's more suitable for use in this project. This can be done using the package github.com/nais/api/pkg/apiclient.

If there's any missing functionality, we'll happily add them to make the switch easier :)

[Starefossen]

Thanks for the heads up, I'll schedule some time to get this implemented!