refactor: refactor the SMTP sender

app/lib/smtp_client/ssl_modes.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module SMTPClient
+  module SSLModes
+
+    AUTO = "Auto"
+    STARTTLS = "STARTLS"
+    TLS = "TLS"
+    NONE = "None"
+
+  end
+end