wip: Add instance field to UtilizationSample and update related queries (#112)

* wip: Add instance field to UtilizationSample and update related queries

* fix: Make instance field in UtilizationSample non-nullable

* chore: Remove unused utilization client initialization from ConfigureGraph

* refactor: Simplify client initialization and remove hardcoded environment variables

* fix: Add namespace and pod labels to metrics in fake tests

* format

* Delete unwanted test files

* fix: Add missing line breaks in client and fake client code

Author: rbjornstad