bitwardenAttachmentByRef filename args

bitwardenAttachmentByRef returns a document from Bitwarden using the Bitwarden CLI (bw). This method requires two calls to bw to complete:

1. First, args are passed to bw get in order to retrieve the item's itemid.
2. Then, filename and itemid are passed to bw get attachment $FILENAME --itemid $ITEMID and the output from bw is returned.

The output from bw is cached so calling bitwardenAttachmentByRef multiple times with the same filename and itemid will only invoke bw once.

!!! example

```
{{- bitwardenAttachmentByRef "$FILENAME" "$ARGS" -}}
```

!!! example

```
{{- bitwardenAttachmentByRef "id_rsa" "item" "example.com" -}}
```