bootstrap modules begone

At this point, I think dropping the bootstrap flag from system table would just work as the bootstrap invoker calls module_implements which is registry based and loads on demand. I would suspect that calling module_invoke_all would work as well, we can drop bootstrap_invoke_all as well. module_list can lose its $bootstrap flag as well as there is no sensible notion of that any more. Once that's done the function will return the list of enabled modules so let's rename it to that. We can have a module_list_loaded which just is a wrapper around drupal_load.... 'cos you know registry_check_code really should use drupal_load. if this awfully resembles the total module revamp, well, we are getting there :)