Server session: New expiration notification system

[juancp-contidosdixitais]

Some teachers use lessons with a minimum duration time that requires students to stay connected for a certain period to progress and move on to the next lesson.

The problem arises when a student leaves the lesson inactive and returns to it after some time, usually a long time. When they do, their progress timer still displays the elapsed time, but in reality, if the session lasts, for example, two hours and eight hours have passed, the student is unaware because they do not receive a notification that their session has expired.

We have built a session expiration system that, after a certain amount of time, displays a screen indicating the session has expired, and even shows a countdown in the last few seconds.

Initially, this would require a subprocess that checks every X seconds for the remaining session time. This subprocess would need to be analyzed to determine if its execution would extend the session, which would be an undesirable effect.

When a user's session has expired, the system hides the entire campus with a black screen and indicates the end of the session.

This PR references this issue: #4776

This session control can be enabled from configuration.php by setting the 'session_lifetime_controller' option to true.