Introducing Window Query + DataFrame API

[JulienPeloton]

This PR re-introduces the Window query method, but with the DataFrame API.

The core of the routine remains untouched (using RDD), but the I/O are different. It takes a DataFrame as input, and return a DataFrame containing the coordinates of the objects found in the window.

[codecov-io]

Codecov Report

Merging #112 into master will increase coverage by 1.07%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #112      +/-   ##
=========================================
+ Coverage   89.72%   90.8%   +1.07%     
=========================================
  Files          32      33       +1     
  Lines        1178    1229      +51     
  Branches      194     202       +8     
=========================================
+ Hits         1057    1116      +59     
+ Misses        121     113       -8

Flag	Coverage Δ
#python	93.65% <ø> (+2.4%)	⬆️
#scala	89.54% <100%> (+0.46%)	⬆️

Impacted Files	Coverage Δ
src/main/scala/com/spark3d/Queries.scala	100% <100%> (ø)	⬆️
...cala/com/spark3d/spatialOperator/WindowQuery.scala	100% <100%> (ø)
src/main/scala/com/spark3d/utils/Utils.scala	97.05% <0%> (+2.94%)	⬆️
queries.py	100% <0%> (+58.33%)	⬆️

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