Set the email onion domain as hostname on onion only installs

src/freedombone-utils-final

     systemctl enable firststart
 }
 
+function final_set_onion_hostname {
+    if [[ "$ONION_ONLY" == 'no' ]]; then
+        return
+    fi
+
+    if [ ! -f /var/lib/tor/hidden_service_email/hostname ]; then
+        echo $'No onion domain for email was found'
+        exit 368365
+    fi
+    onion_domain=$(cat /var/lib/tor/hidden_service_email/hostname)
+    echo "$onion_domain" > /etc/hostname
+    hostname "$onion_domain"
+}
+
 function setup_final {
     function_check update_installed_apps_list
     update_installed_apps_list
     function_check create_default_user_removal_daemon
     create_default_user_removal_daemon
 
+    function_check final_set_onion_hostname
+    final_set_onion_hostname
+
     function_check install_tripwire
     install_tripwire