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.

roles/bitwarden_rs/defaults/main.yml

@@ -0,0 +1 @@
+bitwarden_domain: https://{{ bitwarden_host }}

roles/bitwarden_rs/templates/bitwarden.httpd.conf.j2

@@ -16,6 +16,10 @@ Header always set \
 	Strict-Transport-Security "max-age=63072000; includeSubDomains"
 
 RewriteEngine On
+{% if bitwarden_host is defined %}
+RewriteCond %{SERVER_NAME} !{{ bitwarden_host }}
+RewriteRule /.* https://{{ bitwarden_host }}$0
+{% endif %}
 RewriteCond %{HTTP:Upgrade} =websocket [NC]
 RewriteRule /notifications/hub(.*) ws://localhost:3012/$1 [QSA,P,L]