Add a Pomodoro timer to the extension

[JeremieLitzler]

The Pomodoro Technique is a time management method that can be broken down into several key principles:

• Work intervals: The core of the technique is working in focused 25-minute intervals, called "Pomodoros."
• Short breaks: After each Pomodoro, take a short 5-minute break.
• Long breaks: After completing four Pomodoros, take a longer 15-30 minute break.
• Task division: Break down larger tasks into smaller, manageable units that can fit within a Pomodoro.
• Tracking: Keep a record of completed Pomodoros and tasks.
• Continuous improvement: Use the data from tracking to improve your time estimates and productivity.
• Limiting interruptions: During a Pomodoro, avoid distractions and defer interruptions until the break.

To implement this in code, you might consider the following components:

• A timer function to track Pomodoros and breaks
• A task list or queue to manage and track tasks
• A counter to keep track of completed Pomodoros
• Functions to handle starting/stopping timers and transitioning between work and break periods
• A way to log completed tasks and Pomodoros
• A notification system for when timers end (just like the other extension)