* Allow returning list information and other data in 404s.
On read it'll output data and/or warnings on a 404 if they exist. On
list, the same behavior; the actual 'vault list' command doesn't change
behavior though in terms of output unless there are no actual keys (so
it doesn't just magically show other data).
This corrects some assumptions in response_util and wrapping.go; it also
corrects a few places in the latter where it could leak a (useless)
token in some error cases.
* Use same 404 logic in delete/put too
* Add the same secret parsing logic to the KV request functions
* Add more cli subcommands
* Add metadata commands
* Add more subcommands
* Update cli
* Move archive commands to delete
* Add helpers for making http calls to the kv backend
* rename cli header
* Format the various maps from kv
* Add list command
* Update help text
* Add a command to enable versioning on a backend
* Rename enable-versions command
* Some review feedback
* Fix listing of top level keys
* Fix issue when metadata is nil
* Add test for lising top level keys
* Fix some typos
* Add a note about deleting all versions
