PUBAPI-1234 Add snapshots to node-triton
CR updates.
- add 'triton fwrule update ID <TAB>' completion on updatable fields
- make ID arg first in ^^
- make 'triton fwrule create ...' have the rule enabled by default
- cosmetic help output tweaks
- allow 'triton fwrule update ...' to not *require* that the rule is
updated. i.e you can update just the description