Use custom identifiers in password-manager

`short_key_listing` omits much of the information necessary to uniquely
identify a key.  So, parse the attributes manually, emitting the ones we
need.
`pw` = simple menu for passwords
Default `pw` to github if in a browser
Pass `password-manager` options in list format

Allows setting options from the same input format as the `-l/--list`
option produces.
Skip `user@` if user is default
Allow `-S/--secret` to print associated secrets
Add `table-flip` command

(╯°□°)╯︵ ┻━┻

BECAUSE I'M USING IT THAT FREQUENTLY