Major refactor of acf.py

[RemingtonRohel]

Scope

• Changed all classmethods to staticmethods
• Created staticmethod plot_acf_param() to handle plotting of values, which is called within plot_acfs() as needed to plot real, imaginary, power, and phase of ACF
• Return all axes from plot_acfs() as list
• Plot real and imaginary ACF values on input ax to plot_acfs() if pwr_and_phs False, otherwise use plt.gca()
• Removed some unnecessary internal variables in plot_acfs().
• Proper handling of markers for blanked lags, taking into consideration if marker is a filled marker or not

issue: N/A

Approval

Number of approvals: 1

Test

matplotlib version: 3.7.2

Try running the tutorial from https://pydarn.readthedocs.io/en/main/user/acf/, and using as many of the optional arguments as you can.

[RemingtonRohel]

Made another commit as I realized I had inadvertently changed the phase plotting to plot in radians. It is now back to plotting in degrees.