Convert temporary password storing String to more secure Type in Powershell

Powershell automatically recommended to store the String that temporarily stores the password during installation, in a differrent type than String. It is a good exercise to implement, additionally try to find out how this new type can be passed securely to the Java .jar as argument.

(Note, do not generate a false sense of security just by changing the type, since it still has to be passed to the .jar file which currently still happens as a String type.)