make the camera visualization window flexible

[XX-Yin]

Different rigs may require different camera visualization layout, which makes sense to have a flexible way to change the layout based on camera settings.

Bruno suggested

If the cameras are hardcoded, I think the best you can do without a substantial amount of work is to have 2 layout files that are passed via the command line interface (https://bonsai-rx.org/docs/articles/cli.html#specifying-layout-files-in-application-mode) and probably ensure that the application does not try to connect with the non-existing camera (see #190 (comment)).

If a deeper code refactoring is on the table, I would probably suggest adopting a procedural generation pattern that works with any number of connected cameras. See the the Aind.Behavior.VideoEncodingBenchmarks repository for an example on how to implement this.