Print ALIST_STR, ALIST_DIR and PLUGIN_NAMES as quoted strings.

Update config pretty printer to print certain config types as quoted
strings and not as unquoted ones. This makes things more failsafe if
we use the printed config as input for the actual config eventually.

src/lib/res.c

@@ -1726,7 +1726,7 @@ bool BRSRES::print_config(POOL_MEM &buff, bool hide_sensitive_data)
                      continue;
                   }
                }
-               Mmsg(temp, "%s = %s\n", items[i].name, value);
+               Mmsg(temp, "%s = \"%s\"\n", items[i].name, value);
                indent_config_item(cfg_str, 1, temp.c_str());
             }
          }