Add CAP_JAIL_ATTACH, CAP_JAIL_REMOVE, and CAP_JAIL_SET,
and use them when JAIL_USE_DESC
on jail_attach_jd(2), jail_remove_jd(2), and jail_set(2).
Note that that rights are attenuated according to creds
at descriptor creation.
Co-authored-by: Runxi Yu <runxiyu@umich.edu>