mm: backport folio support

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2019485
Tested: ran Rafael's set of sanity tests with a stock kernel test run for comparison

This backport includes the base folio patches without touching any subsystems.
Patches are mostly straight forward converting functions to use folios.

v2: merge conflict, dropped 78525c74d9e7d1a6ce69bd4388f045f6e474a20b as contradicts the fact we're trying to not do subsystems converting in this MR

Signed-off-by: Aristeu Rozanski arozansk@redhat.com