REF: use BlockManager.apply in csv code
This doesn't get rid of internals usage entirely, but makes that access 1 layer less deep
@jbrockmendel needs a rebase, but I agree @jorisvandenbossche suggsetion might be good in this PR just rebased.  i encourage @jorisvandenbossche to push the edit he has in mind thanks @jbrockmendel 

yeah agree that followups to push down to_native_types makes sense 