Bumping compile time requirement to go 1.18 allows us to simplify our pointer helper methods.
This is a followup to running tests in serial in CI. Since the API package cannot import anything outside of api/, copy the ci.Parallel function into api/internal/testutil, and have api tests use that.
`helpers.FormatFloat` function is only used in `api`. Moving it and marking it as private. We can re-export it if we find value later.