Refactor e2e tests

Makefile

cmd/flux/get.go

cmd/flux/helmrelease_test.go

cmd/flux/install_test.go

cmd/flux/kustomization_test.go

cmd/flux/main_e2e_test.go

cmd/flux/main_test.go

cmd/flux/main_unit_test.go

...x/testdata/helmrelease/create_helmrelease_from_git.golden

cmd/flux/testdata/helmrelease/create_source_git.golden

...x/testdata/helmrelease/delete_helmrelease_from_git.golden

...flux/testdata/helmrelease/get_helmrelease_from_git.golden

...estdata/helmrelease/reconcile_helmrelease_from_git.golden

...x/testdata/helmrelease/resume_helmrelease_from_git.golden

.../testdata/helmrelease/suspend_helmrelease_from_git.golden

cmd/flux/testdata/install/install_extra_components.golden

cmd/flux/testdata/install/install_no_args.golden

...stdata/kustomization/create_kustomization_from_git.golden

cmd/flux/testdata/kustomization/create_source_git.golden

...stdata/kustomization/delete_kustomization_from_git.golden