Add abillity to pause the timer

[colinkiama]

Feature Request

Is your feature request related to a problem? Please describe.
Add ability to pause the timer. Sometimes we're not always at our desk (e.g needing to go toilet) but we shouldn't continue to lose time.

Describe the solution you'd like
A pause button should be added for sessions in progress.

Describe alternatives you've considered
N/A

Additional context
N/A

[Zyten]

That goes against the Pomodoro principles I think. IINM we're supposed to fully commit to the 25 minutes task and take a 5 min break afterwards to reward. In urgent cases where we have to break our focus, we're meant to stop the timer and reset when we get back.

But that gave me an idea, perhaps a feature to track how often we're stopping the clock prematurely might be useful?