auth: Allow subnet ranges in NetInfo and NetRestrict

auth: Allow subnet ranges in NetInfo and NetRestrict

Add the ability to specify a range of addresses in both NetInfo and
NetRestrict.

Change-Id: Iecdcca8587aa2e6e7cd56cbbebb63eb41b5d6f40
Reviewed-on: https://gerrit.openafs.org/11313
Reviewed-by: Daria Phoebe Brashear <shadow@your-file-system.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>