Add plotting enhancements

[justin-richling]

New feature type

New plot and/or plot enhancement

What is this new feature?

Add flexibility for plotting (contour levels, colormap, etc.) based on pressure level and/or plot type (polar vs global)

Update plots for more professional look, ie Zonal and Meridional are very bare boned, lat/lon were missing units, some variables were not getting proper scaling, fit colorbar better to axes and extend if necessary, etc.

• NOTE: There is an additional enhancement for 2d line plots for Zonal/Meridional that allows a color map for the 2d variables (See SWCF example below - variable defaults argument: colormap_2d)

Combine Lat/Lon Vector into Lat/Lon code since it was a lot of reused code.

• NOTE: the calculation for percent difference is currently off for lat/lon vectors plots, so this map is being ignored and vector plots default back to the two cases on top and difference centered below

Add option in variable defaults config for variable nickname; remove all percent diff args in defaults yaml and hard code in plotting script. The user will still have the option to supply these args in the yaml file if default is not desired.

Add option for old NCL color maps

Add units cleaning method to ensure units are always available, this was not enforced throughout the code base.

Add code to resolve levels for hemisphere and resolve colormap in prep_contour_plot

---

Core new features:

Different contours based on vertical levels

RESTOM:
  colormap: "RdBu_r"
  contour_levels_range: [-100, 101, 5]
  diff_contour_range: [-10, 10, 0.5]
  polar_map:
    colormap:
      nh: "RdBu_r"
      sh: "terrain"
    contour_levels_range:
      #nh: [-100, 101, 5]
      sh: [-100, 0, 2.5]
   scale_factor: 1
  add_offset: 0
  new_unit: "W m$^{-2}$"
  category: "TOA energy flux"
  derivable_from: ['FLNT','FSNT']

---

SWCF:
  colormap: "Reds"
  polar_map:
    colormap:
      nh: "fakemap"
      sh: "Blues"
  contour_levels_range: [-150, 51, 10]
  diff_colormap: "BrBG"
  diff_contour_range: [-20, 21, 2]
  scale_factor: 1
  add_offset: 0
  new_unit: "Wm$^{-2}$"
  obs_file: "CERES_EBAF_Ed4.1_2001-2020.nc"
  obs_name: "CERES_EBAF_Ed4.1"
  obs_var_name: "toa_cre_sw_mon"
  obs_scale_factor: 1
  obs_add_offset: 0
  category: "TOA energy flux"
  colormap_2d: True

---

U:
  global_latlon_map:
    colormap: # if not specified, default to viridis for any missing values nested (levs, ie 850) or not
      200: "ncl_default"
      #850: "Spectral"
    contour_levels_range:
      200: [-10, 51, 2.5]
      850: [-10, 31, 2.5]
    diff_contour_range:
      200: [-15, 16, 2]
      850: [-5, 5.1, 0.5]
  polar_map:
    colormap:
      nh: "terrain"
      sh: "fake_cmap"
    contour_levels_range:
      nh:
        200: [-10, 31, 2.5]
        850: [-10, 13, 1]
      sh:
        200: [-10, 51, 5]
        850: [-10, 31, 2.5]
    diff_contour_range:
      200: [-10, 10, 1]
      850: [-5, 5.1, 0.5]
      #nh:
      #  200: [-15, 16, 2]
      #  850: [-5, 5.1, 0.5]
      #sh:
      #  200: [-15, 16, 2]
      #  850: [-5, 5.1, 0.5]
  zonal_mean:
    colormap: "ncl_default"
    contour_levels_linspace: [-10, 30, 15] # These will be applied to all zonal 3d mean plots
    #diff_contour_range: # default to figuring our the contour levels from difference from max/min
  scale_factor: 1
  add_offset: 0
  new_unit: "ms$^{-1}$"
  obs_file: "U_ERA5_monthly_climo_197901-202112.nc"
  obs_name: "ERA5"
  obs_var_name: "U"
  vector_pair: "V"
  vector_name: "Wind"
  category: "State"

---

Surface_Wind_Stress:
  nickname: "Surface Wind Stress"
  new_unit: "N m$^{-2}$"
  category: "Surface variables"

TAUX:
  new_unit: "N m$^{-2}$"
  vector_pair: "TAUY"
  vector_name: "Surface_Wind_Stress"
  category: "Surface variables"
  scale_factor: -1
  add_offset: 0

TAUY:
  new_unit: "N m$^{-2}$"
  vector_pair: "TAUX"
  vector_name: "Surface_Wind_Stress"
  category: "Surface variables"
  scale_factor: -1
  add_offset: 0

---

closes #452
closes #425
closes #373