[FEATURE] Stopwatch mode on timer plugin

[9Prestidigitator]

Submission checklist

• I have searched existing issues and confirmed this has not been requested before.
• I have checked existing pull requests for similar changes.

Feature type

New functionality

Feature summary

Similar to noctalia-v4's timer plugin where there is toggle between a classic timer and a stopwatch that continuously counts up.

Motivation / use case

I have been leetcoding a lot and a stopwatch makes more sense to me than a classic timer. Especially one built into my shell.

Proposed solution

Add a tab or button on the bottom of the panel and/or in the desktop widget settings that switches it between a stopwatch/timer.

Alternatives considered

No response

References / related projects

No response

Additional context

No response