Load more SMTP settings from environment vars

Ignoring SSL/TLS/STARTTLS for now, that should be fine left on auto these days.

config/application.rb

@@ -59,10 +59,14 @@ module Manyfold
 
     config.action_mailer.smtp_settings = {
       address: ENV.fetch("SMTP_SERVER", nil),
+      port: ENV.fetch("SMTP_PORT", nil),
+      domain: ENV.fetch("SMTP_DOMAIN", nil),
       user_name: ENV.fetch("SMTP_USERNAME", nil),
       password: ENV.fetch("SMTP_PASSWORD", nil),
-      port: ENV.fetch("SMTP_PORT", nil),
-      openssl_verify_mode: (ENV.fetch("SMTP_VERIFY_SSL_MODE", nil) == "none") ? :none : nil
+      authentication: ENV.fetch("SMTP_AUTHENTICATION", nil)&.to_sym,
+      openssl_verify_mode: ENV.fetch("SMTP_OPENSSL_VERIFY_MODE", nil)&.to_sym,
+      open_timeout: ENV.fetch("SMTP_OPEN_TIMEOUT", nil)&.to_i,
+      read_timeout: ENV.fetch("SMTP_READ_TIMEOUT", nil)&.to_i
     }.compact
 
     # Load some feature settings from ENV