tests: Move netpfil/pf/divapp to netpfil/common/

[igoro]

It's planned to be used by pf and ipfw tests, the latter will be added with a separate patch.

[markj]

You'll also want to add an entry to Obsoletefiles.inc so that the old binary gets removed when folks do source-based upgrades. (Keeping the old binary around doesn't hurt, of course, but it should be cleaned up anyway.)

[igoro]

Update ObsoleteFiles.inc respectively

[kp]

Approved, but maybe give Olivier a few more days to chime in.