[FEATURE] Time tracking widget for significant events

[onesvat]

In this pull request, I've added a new feature: a time tracking widget.

This straightforward widget has two main functionalities:

• Counting down to positive upcoming events such as holidays.
• Counting up from the start of a new habit or the end of a bad one, like quitting smoking.

The widget is user-friendly and requires only the event and timing as inputs.

I look forward to hearing your thoughts on this feature and any potential improvements.