Get terminal title

[carrascomj]

Is your feature request related to a problem? Please describe.

In some TUI applications (like a text editor), the window title might be modified to display some information (see for example helix-editor/helix#928) and that's already implemented here. However, it is desirable to also revert it back to what it was in the first place, but there's no option to get the title to store it before setting it.

Describe the solution you'd like

As an user, I would like to have a title getter function, complementary to SetTitle and in the same fashion as size.

Describe alternatives you've considered in any
The user could always interact with the lower-level underlying libraries and that would require to handle different platforms, which I guess it is not desirable. I think it makes sense to provide the Getter/Setter pair.

Additional context
Anything else?