Display the Client window based on the window-override settings

The client window should always be on top even if there are popups like update dialogues. Saves us the pain to go into different machines and remove the popups. If there are any popups they will be behind the xibo client. Similar to what the nexus digital signage does.

The client can be push to back if there is a higher priority window. Will be helpful to display some other window when it opens up such as a campus wide alert message which opens up if there is an emergency. This can be useful if the campus uses a different alerts system and not the xibo itself for displaying the alerts. There is another blueprint which is for integrating alerts into the xibo by having an alert end point tied into the settings. But this can work till that is incorporated into the xibo project. Also it can compliment it if they choose to use their own alert window system.

Task manager is always on top if brought up.

The window priority is registered in the client settings.

for dotnet client.