Add ability for vectorfield to instantiate from_uv

[ahuang11]

Closes #3486

import pandas as pd
import numpy as np
import holoviews as hv
hv.extension("bokeh")

x = np.linspace(-1, 1, 4)
X, Y = np.meshgrid(x, x)
U, V = 5 * X, 5 * Y

df = pd.DataFrame({
    "x": X.flatten(),
    "y": Y.flatten(),
    "u": U.flatten(),
    "v": V.flatten(),
})

hv.VectorField.from_uv(df, ["x", "y"], ["u", "v"])

[codecov-commenter]

Codecov Report

Merging #5797 (13a80ec) into main (53111a9) will increase coverage by 0.00%.
The diff coverage is 97.95%.

@@           Coverage Diff           @@
##             main    #5797   +/-   ##
=======================================
  Coverage   88.14%   88.15%           
=======================================
  Files         307      307           
  Lines       62841    62912   +71     
=======================================
+ Hits        55394    55461   +67     
- Misses       7447     7451    +4     

Flag	Coverage Δ
ui-tests	22.40% <10.20%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
holoviews/element/geom.py	97.50% <94.73%> (-2.50%)	⬇️
...oloviews/tests/element/test_elementconstructors.py	98.90% <100.00%> (+0.21%)	⬆️

... and 5 files with indirect coverage changes

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[philippjfr]

Looks great!