Add a changelog in Oneteam

Context: Today there is no notification where users can see what has recently changed or been added to the product. As a result, new features and improvements can go unnoticed, and there is no clear signal that something new is available to read.

Desired solution:
- A changelog within Oneteam where users can view recent product updates and changes
- A clear way to surface when a new update is available, such as a notification indicator (e.g. a red dot)
- Relocating the help button to a corner of the screen where this indicator is easy to spot, so a new-update marker is immediately noticeable