tar: move package to 'system tools'

Package was previously in the 'Development' section

Signed-off-by: Francesco Nwokeka <francesco.nwokeka@gmail.com>
Reviewed-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Tested-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>