feat: expected progress bars

[GursheenK]

Description
Introduces a new option show_expected_progress to be passed to the Gantt constructor in order to enable expected progress bars for each task depending upon the current date.

Screen Recording

Screen.Recording.2023-11-20.at.1.06.24.AM.mov

Closes #281

[GursheenK]

@cfontes In the changes made, I have interpreted that the estimate progress is supposed to be a projection of the task's unit progress with respect to the current date.

Can you please elaborate on whether there are other parameters the estimate should consider and / or a simple example of such an estimate for any task?

[cfontes]

Hello @GursheenK so one this one is being worked on...

What I wanted is a bit different though, I wanted to have the original estimation, forever imprintedf on the back of the chart as a shadow ( maybe with some bubble for info on start and end date, and option to change them id needed )

That way when you drag the current work it stays behing so you know you did a bad job estimating the start and duration of it and can come back later, to improve