fix: do not use DNS challenge for root domain TLS

Previous solution made ACME create two TXT records
on the same subdomain, creating the conflict

letsencrypt/acme.nix

@@ -17,7 +17,6 @@ in
     certs = lib.mkForce {
       "${cfg.domain}" = {
         domain = "*.${cfg.domain}";
-        extraDomainNames = [ "${cfg.domain}" ];
         group = "acmerecievers";
         dnsProvider = lib.strings.toLower cfg.dns.provider;
         credentialsFile = "/var/lib/cloudflare/Credentials.ini";

webserver/nginx.nix

@@ -20,8 +20,7 @@ in
 
     virtualHosts = {
       "${domain}" = {
-        sslCertificate = "/var/lib/acme/${domain}/fullchain.pem";
-        sslCertificateKey = "/var/lib/acme/${domain}/key.pem";
+        enableACME = true;
         forceSSL = true;
         extraConfig = ''
           add_header Strict-Transport-Security $hsts_header;