Bitwarden can store multiple different types of items in the vault, such
as credit cards and "secure notes." These are not useful in the context
of `bwpass`, so they can be ignored when loading items from the vault.
The `bwpass` command attempts to replicate the main functionality of
`pass` on top of `bw`. Since `bw` is incredibly slow, it tries to avoid
spawning it whenever possible by caching the list of items. It also
manages the Bitwarden CLI session by reading the session token from a
file. If the file does not exist, it will prompt for the vault master
password using `pinentry`, unlock the session, and store the new token.
