Convert jls to use libxo

[• rodrigc]

Summary

This was originally submitted under PR 200746.
I modified the patch slightly based on my
experience reviewing allanjude's conversion of procstat to libxo.

Test Plan

Create some jails.
Run:
jls
jls -N
jls -h
jls --libxo json,pretty
jls --libxo json,pretty -N
jls --libxo json,pretty -h

[• rodrigc]

Remove stdout

[allanjude]

usr.sbin/jls/jls.c

209

missing close }, bad padding, doesn't line up correctly

217

padding off by 1

391

instead of doing {e:hostname/%s}{d:hostname/%-29.29s} you can use the shorthand: {:hostname/%-29.29s/%s}

391

The path shouldn't get truncated

411

now the output is no longer padded to 15 characters. This is probably ok, but it does change the plain-text output (by removing space characters after the end of the line)

528

could the libxo 'quotes modifier' help here?

[allanjude]

Fix some problems found during my review

[• rodrigc]