Revise ToDoList installation guide for Ubuntu

[ivangretsky]

Updated installation instructions for ToDoList on Ubuntu, including important notes, required packages, and steps to create a desktop launcher.

A years-later follow-up on this)))

Would be useful to mention it here but I didn't find DokuWiki source files in github.

[abstractspoon]

Hi ivangretsky

Thanks-you for your contribution.

Would it be possible to work this into the existing Linux installation notes rather than creating a new file.

I understand that Markdown offers formatting possibilities but I would much prefer sticking with the existing file format and name,

Let me know