refactor: rephrase init script description to not mention cloud-init

Depending on the template, it might not be a cloud-init one.
Rephrase to avoid confusion.

Author: scop

modules/servers/upCloudVps/lang/english.php

@@ -8,7 +8,7 @@
 $_LANG["OS"] = "Operating System";
 $_LANG["location"] = "Location";
 $_LANG["sshRsa"] = "Provide SSH public key in OpenSSH format";
-$_LANG["userData"] = "Cloud-init script for early initialization of cloud instances";
+$_LANG["userData"] = "Script for early initialization of cloud instances";
 $_LANG["Hostname"] = "Hostname";
 $_LANG["VMId"] = "VPS ID";
 $_LANG["Template"] = "Template";