Add checkbox for icensed_seat_info_available

[thenikola]

It would be a nice feature addition if there were a tickbox that would allow you to add licensed seat tracking to pkgsinfos licensed_seat_info_available

https://code.google.com/p/munki/wiki/LicenseSeatTracking

This also requires users to run MunkiWebAdmin server, however currently, admins have to add this line to their pksinfos manually.

[hjuutilainen]

Thanks for the feature request. I'm not using this feature in MunkiWebAdmin so this pkginfo key has gone completely unnoticed. Will add this in a future release.