Improve speed of switching between settings and main window

[gavinhenderson]

Is your feature request related to a problem? Please describe.
When you open and close settings it can be quite slow to get the camera loaded again. Ideally we should be able to jump right back into the main window from settings

Describe the solution you'd like
It should load the main window straight away or not even refresh at all

Additional context
The reason behind this slowness is because it does a full application refresh to make sure every part of the app has the latest settings. Ideally we should just be able to update the parts of the app that need updating. This will require careful state management so we dont get out of date settings

Message NG once done