Implemented emulator for #190

[simonmicro]

Closes #190

Still needs (merge into this branch to implement them):

• @simonmicro CI support
• @simonmicro Maybe fix history and accidental removed files (so we have no additional commits re-adding them)
• @simonmicro Virtual sensor support in the UI
• @simonmicro The config support from Emulator: add web interface virtual mode #287
• @RuffaloLavoisier Docker information into README.md
• Emulator remember window size (so arranged windows of ImGUI stay where they were)
• Undock (?) watch display, so it is just inside its own window
  • Change emulator bg?
• Show section labels

[RuffaloLavoisier]

I think it'd be nice to create a docker usage on the Readme(self assignment me :) )and create a developer section add emulator parts to the official documents.

Developer
- dev tool (emulator)

[RuffaloLavoisier]

How about you to re-implement a circular surface of the watch?
This allows you to see the maximum value and exactly where it is on the face of the clock as you proceed with the UI operation. (You can see if the drawn image or text is off the clock boundary)

See : https://github.com/Open-Smartwatch/lib-open-smartwatch/blob/267d00a2ac76a70dc5a589af4bfa1ce05b70d744/FakeArduinoWindowSDL.h#L113

[simonmicro]

How about you to re-implement a circular surface of the watch? This allows you to see the maximum value and exactly where it is on the face of the clock as you proceed with the UI operation. (You can see if the drawn image or text is off the clock boundary)

See : https://github.com/Open-Smartwatch/lib-open-smartwatch/blob/267d00a2ac76a70dc5a589af4bfa1ce05b70d744/FakeArduinoWindowSDL.h#L113

We could add this to the FakeDisplay or (better) OswUI instance and control that "underlay" using a public accessible boolean (like the way how I can disable the framerate limiter.

[RuffaloLavoisier]

Looks Good To Me, The minor point has been modified inside.