Include www subdomain in clearnet TLS issuance.

Request apex and www from Let's Encrypt and serve both names in nginx.

nginx/conf.d/clearnet.conf.template

@@ -1,6 +1,6 @@
 server {
     listen 80;
-    server_name ${CLEARNET_DOMAIN};
+    server_name ${CLEARNET_DOMAIN} www.${CLEARNET_DOMAIN};
 
     location /.well-known/acme-challenge/ {
         root /var/www/certbot;
@@ -13,7 +13,7 @@ server {
 
 server {
     listen 443 ssl;
-    server_name ${CLEARNET_DOMAIN};
+    server_name ${CLEARNET_DOMAIN} www.${CLEARNET_DOMAIN};
 
     ssl_certificate /etc/nginx/certs/live/${CLEARNET_DOMAIN}/fullchain.pem;
     ssl_certificate_key /etc/nginx/certs/live/${CLEARNET_DOMAIN}/privkey.pem;