split stat_attrs into cheap and expensive part
split stat_attrs into cheap and expensive part

we already have stat results in st, so computing stat_simple_attrs is
rather cheap (except the username/groupname lookup maybe) and gets the
most important stuff right in the Item, so it is brought early into a
good state.

after chunking, stat_ext_attrs is called to add the more expensive-to-get
attributes, like bsdflags, xattrs and ACLs.

edgewood/borg,raxenak/borg,RonnyPfannschmidt/borg,edgimar/borg,RonnyPfannschmidt/borg,RonnyPfannschmidt/borg,edgimar/borg,edgewood/borg,edgewood/borg,edgimar/borg,raxenak/borg,edgewood/borg,edgimar/borg,raxenak/borg,RonnyPfannschmidt/borg,raxenak/borg,RonnyPfannschmidt/borg