Use example values instead of default during install, var renmaing

config_panel.toml

@@ -5,13 +5,13 @@ name = "InvoicNinja configuration"
     [main.config]
     name = "Configuration Options"
 
-        [main.config.mail_address]
+        [main.config.default_from_email_address]
         ask.en = "Choose from which mail address emails will be sent"
         ask.fr = "Choisissez à partir de quelle adresse e-mail les e-mails seront envoyés"
         help = "Default email address to use for various automated emails."
         bind = "MAIL_FROM_ADDRESS:__INSTALL_DIR__/.env"
 
-        [main.config.mail_name]
+        [main.config.default_from_email_name]
         ask.en = "Choose what name will be displayed when InvoiceNinja sends mails"
         ask.fr = "Choisissez quel nom sera affiché lorsque InvoiceNinja enverra des e-mails"
         help = "Default name address to use for various automated names."