[Feat] Single-Window GUI: Set up new events for AuiNotebook

[lindakarlovska]

*Is your feature request related to a problem? Please describe.
Firstly several two Issues were made addressing new Single-Window GUI event stuff. However, later we decided to make just one Issue. The below-mentioned separate Issues are closed now and merged into this Issue dealing with two new events:

• Add a new closing event for the AuiNotebook tab. This event should close the related Display tab. ([Feat] Single-Window GUI events: Close AuiNotebook tab #1740)

• Add a new event for switching between AuiNotebook tabs. This event should make the related Display tab active. ([Feat] Single-Window GUI events: Switch between AuiNotebook tabs #1744)

It is important to emphasize that both types of events (for the AuiNotebook as well as for the Display pane) cannot be based on the current AuiNotebook tab index because of the order of tabs in AuiNotebook which is changeable. So we will probably need to implement a bit different logic to cope with that.

[lindakarlovska]

Solved.