view: support scatter plot via --style scatter option

[falkamelung]

Description of proposed changes

This PR supports the scatter plot via matplotlib.pyplot.scatter(), in addition to the existing image plot via matplotlib.pyplot.imshow(), for view.py single plot scenario. This is useful for high-resolution data with lots of holes from unsuccessful unwrapping. Plotting larger than pixel size fills holes like a low-pass filter.

This is controlled via two options: --style with default of image, and --scatter-size with default of 10 point (**2), respectively.

In the image, top is regular view.py (using imshow) and bottom is --style scatter --scatter-size 8

Reminders

• Pass Pre-commit check (green)
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• Pass Circle CI test (green)
• Make sure that your code follows our style. Use the other functions/files as a basis.
• If modifying functionality, describe changes to function behavior and arguments in a comment below the function declaration.
• If adding new functionality, add a detailed description to the documentation and/or an example.

[yunjunz]

Thank you @falkamelung for the PR. The new style looks nice!