lib/pull: Add status for imported objects

lib/pull: Add status for imported objects

Followup for recent work in commits:

 - 8a7a35970928331a028ccddd04590ac300dbd26e
 - 1a9a473580e9066f5d4a969932d703b5b104b2b7

Keep track of how many objects we imported, and print that for `ostree
pull-local` (also do this even if noninteractive, like we did for `pull`).

In implementing this at first I used separate variables for import
from repo vs import from localcache, but that broke some of the
tests that checked those values.

It's easier to just merge them; we know from looking at whether or not
`remote_repo_local` is set whether or not we were doing a "HTTP pull with
localcache" versus a true `pull-local` and can use that when rendering status.

Closes: #1219
Approved by: jlebon