Difference handling needed on Visibility vs Focus for the Views

[psaavedra]

Issue Description:

I believe the current implementation suffices for our immediate needs, as we always want the focus activated in the visible view. However, it is apparent that, in the future, we'll need to differentiate between these two distinct concepts: visibility and focus.

Consider the following pseudo-command examples:

1. cog set visible view 3 from viewport 2
2. cog set focus on viewport 2

In the first case, activating the focus on view 3 of viewport 2 should only occur if the focus was previously active on viewport 2. Unfortunately, this won't always be the case. For instance, there may be situations where we wish to make view N of a viewport visible without taking focus away from another viewport, which currently has the focus.

This issue is created to initiate a discussion and explore potential improvements or changes to the behavior to distinguish between visibility and focus, as well as handling situations where focus transition may not be desired. Your input and suggestions @aperezdc are welcome as we work towards a more precise and user-friendly implementation.

• Original motivation from a comment here: Introduce CogViewport, add support in the Wayland plug-in and example program #644 (comment)