Performance enhancement: Allow menu_rebuild() to be skipped

This module can trigger multiple menu rebuilds in one request, e.g. when reverting features.

One way to work around this problem would be adding a parameter to skip menu_rebuild(), which would default to the current behavior. Thus the calling code could call menu_rebuild() just once at the end. See e.g. #2989623: Performance enhancement: Skip menu_rebuild() when deleting multiple pages for how this parameter could be used.

There are other possibilities that I didn't explore, such as registering a shutdown function.