Store powerGate-Server Connection URL on Vault-Server

[lustricker]

@christiangessner

TODO

Extend the powerGateConfigurationTemplate.xml to contain the connection-String to the powerGate Server. This allows the user to modify the connection-string without having to replace the string on every client-machine.

[christiangessner]

@lustricker, thanks for creating this issue. I have this topic on my agenda already and will use this issue to work on it.
It still needs to be defined, if the powerGateConfigurationTemplate.xml is the right way to persist this information.