Change closures to use $app as the first parameter.

Almost always the first parameter is $app therefor it makes little sense
to use `use` part of the closure and having PHP do context switching all
over the place.

This also makes it explicit in the service providers exactly what $app
instance is used.
this is wrong here, as it is a protected closure stored in Pimple, not a service factory. It deos not make sense to force it to receive the app IMO, given that it is an extension point