define instance presets
create helper function for applying instance presets
create presets route, template and controller
no cancel button on preset view

it is part of the instance creation process. The instance
was already created at this point. So canceling at this point
would leave users with an unconfigured instance.
link presets into instance creation workflow
presets form as function
add presets reset to settings
Fix presets_form accidently returning a tuple
Link to instance settings after instance preset dialog

This is coherent with the shown message and generally makes sense.
Adapt flash message after instance creation to preset workflow
Merge pull request #680 from xi/feature-665-presets

Instance presets