NIC facts parsing change

Subclasses does not define their own attributes and serialize them to
attrs hash. All BMC attributes are extracted to separate columns so it's
possible to search NICs by those attributes. Attrs can still be used for
custom attributes (e.g. coming from facts).

NIC form was ajaxified which means that we redraw the form for
particular interface class. We can easily define custom forms for
various interfaces types.

Added support for virtual and physical interfaces. Initial support for bridges
(to keep tests green). Important imported attribute can be set via UI as
well.

IPMI facts parsing and BMC NIC creation

NIC orchestration is now optional and can be set for every interface.
All created interfaces based on facts (BMC or Interface) are not
managed.