[FEATURE] Programatically change core-gui canvas size

[derkin123]

Is your feature request related to a problem? Please describe.
When using the api provided, you are able to use the SessionLocation message to set the fields x, y, z, lat, lon, alt, and scale for the core-gui canvas. It would be nice if you could also set the height and width of the canvas that the gui will be using so this doesn't have to be manually specified.

Describe the solution you'd like
The simplest solution would be to add parameters height and width to the SessionLocation message. You could also create a new message specifically for this but that would require more work to update existing code to.

Describe alternatives you've considered
I know that you are able to change the preferences to automatically set a specific height and width as the default. This is a good solution if you only have one set size you want for all simulations, but the problem still exists if you want to have different sessions with different needs.

Additional context
Add any other context or screenshots about the feature request here.