Add Digital mode for stopwatch tab

[Nekhelesh Ramananthan]

This bug report is to track the digital mode for stopwatch tab. Currently the stopwatch tab is always shown in analogue format. If the user chooses digital format in the settings options, the stopwatch should switch to digital mode. Pressing on the digital text should start or stop the stopwatch similar to the analogue stopwatch.

Difficulty: Medium/Hard

--------- Desired Solution (nik90) -----------------
You might want to consider using a QML loader to ensure that the analogue stopwatch does not waste memory while being in digital mode. Also additional points if the digital text changes color while the mouse cursor hovers over it to indicate that it can be clicked/pressed in desktop mode :)