exec function working dir is the kustomization that referenced it (#4125)

* exec function working dir is the kustomization that referenced it

* suggested changes

* more code review

* use a field instead of an annotation

* more code review

api/types/pluginrestrictions.go

@@ -57,4 +57,6 @@ type FnPluginLoadingOptions struct {
 	Env []string
 	// Run as uid and gid of the command executor
 	AsCurrentUser bool
+	// Run in this working directory
+	WorkingDir string
 }