Don't install Thrust examples, tests, docs, and python files

[robertmaynard]

Prune the amount of Thrust source tree that we install. On top of reducing the size of cudf's install tree, this fixes an
issue where when using cudf via conda-build, conda presumes that all python files inside cudf are valid and part of the package, and fails to parse them.

[jakirkham]

cc @harrism

[kkraus14]

@gpucibot merge

[codecov]

Codecov Report

Merging #7811 (ce72df3) into branch-0.19 (7871e7a) will increase coverage by 0.79%.
The diff coverage is n/a.

❗ Current head ce72df3 differs from pull request most recent head 52039ec. Consider uploading reports for the commit 52039ec to get more accurate results

@@               Coverage Diff               @@
##           branch-0.19    #7811      +/-   ##
===============================================
+ Coverage        81.86%   82.66%   +0.79%     
===============================================
  Files              101      103       +2     
  Lines            16884    17563     +679     
===============================================
+ Hits             13822    14518     +696     
+ Misses            3062     3045      -17     

Impacted Files	Coverage Δ
python/cudf/cudf/utils/dtypes.py	83.44% <0.00%> (-6.08%)	⬇️
python/cudf/cudf/utils/gpu_utils.py	53.65% <0.00%> (-4.88%)	⬇️
python/cudf/cudf/core/column/lists.py	87.32% <0.00%> (-4.08%)	⬇️
python/cudf/cudf/core/column/decimal.py	92.68% <0.00%> (-2.19%)	⬇️
python/dask_cudf/dask_cudf/backends.py	87.50% <0.00%> (-2.13%)	⬇️
python/cudf/cudf/core/abc.py	87.23% <0.00%> (-1.14%)	⬇️
python/cudf/cudf/core/groupby/groupby.py	92.77% <0.00%> (-0.68%)	⬇️
python/cudf/cudf/core/column/column.py	87.61% <0.00%> (-0.15%)	⬇️
python/cudf/cudf/utils/utils.py	85.36% <0.00%> (-0.07%)	⬇️
python/cudf/cudf/io/feather.py	100.00% <0.00%> (ø)
... and 49 more

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