bootstrapping: only web should depend on forms

This fixes the problem that CLI scripts or other applications without
an application directory would badly fail because of missing web forms.

refs #6411
bootstrapping: autoloader exceptions should not...

...require to be autoloaded.

refs #6411
bootstrapping: create only one CLI loader instance

This used to work fine as long as you didn't try to interfere from
outside to influence the cli loader. The instance returned by
cliLoader() was not the same as used internally once dispatching the
CLI command.

refs #6411