When the form folder didn't exist, an exception was thrown that
froze the frontend without any error message. Now it is tested
whether the form folder in a module is available and only registered
in the auotoloader if so.
refs #4407
New namespace implementation created to load application code
like forms with this autoloader. Consumpting services can register
their own, multiple namespaces. Overlapping namespaces matched
by closest name.
refs #4407