[frontend] version2 of VideoFromCV, ServoMotorInstruction and RemainingTime components

[annhit29]

The website frontend version 2 is to be aligned with Computer Vision.

The commits about version 2 are on on the branch wei-en_app-client_end_API_calls as well.

[annhit29]

Frontend v2 for VideoFromCV component, see commit frontend VideoFromCV component add cams selection buttons.

When none of the cameras are selected: When camera 2 (for example) is selected, the camera2 will be on and the Computer Vision part will be displayed in the video field beside the buttons (need the server side):

[annhit29]

Frontend v2 for ServoMotorInstruction component, see commit change the progress bar to ServoMotorInstruction component.

[annhit29]

Frontend v2 for VideoFromCV component contd., I have replaced the video png with the <video> in real-time in the VideoFromCV component.

When the cameras are off, there is no video to display from the cameras, so we see the grey screen:

For now, there is no backend, so no available URL linked to it, so no videos are available to display. The code in the VideoFromCV component

className={`custom-video-controls ${!videoSource && 'placeholder'}`}

means "show the gradient grey background placeholder if the video source is empty and switches to the video feed when a video source is available."

[annhit29]

The RemainingTime component has been removed, its subcomponents are moved into ServoMotorInstruction component. For the 4th component, instead of having the RemainingTime component, we now have a two-octave piano visualizer (the Play component): see issue #62 .