feat(manager/helmfile): Support kustomize (#20782)

lib/modules/manager/helmfile/__fixtures__/multidoc.yaml

...dules/manager/helmfile/__snapshots__/extract.spec.ts.snap

lib/modules/manager/helmfile/artifacts.spec.ts

lib/modules/manager/helmfile/artifacts.ts

lib/modules/manager/helmfile/extract.spec.ts

lib/modules/manager/helmfile/extract.ts

lib/modules/manager/helmfile/types.ts

lib/modules/manager/helmfile/utils.ts

lib/util/exec/containerbase.ts

lib/util/exec/types.ts