r/bitwarden_rs: Redirect to canonical host name

Bitwarden has not worked correctly for clients using the non-canonical
domain name (i.e. _bitwarden.pyrocufflink.blue_) for quite some time.
This still trips me up occasionally, though, so hopefully adding a
server-side redirect will help.  Eventually, I'll probably remove the
non-canonical name entirely.

group_vars/bitwarden_rs.yml

@@ -1,4 +1,4 @@
-bitwarden_domain: https://bitwarden.pyrocufflink.net
+bitwarden_host: bitwarden.pyrocufflink.net
 burp_backup_script_pre: /etc/burp/backup-pre.sh
 burp_backup:
 - include: /var/lib/vaultwarden/data