chore: rename keystone to draft

Rename the module, CLI command name, and all references from
keystone/basalt to draft, and fix the stale build/README content
found along the way.

cmd/service.go

@@ -24,7 +24,7 @@ type ServiceTemplateData struct {
 var serviceCmd = &cobra.Command{
 	Use:   "service",
 	Short: "Create a new service",
-	Long:  `Create a new service for your Keystone project.`,
+	Long:  `Create a new service for your Draft project.`,
 	Run:   genService,
 }