Add gbenchmarks for strings replace regex functions

[davidwendt]

Reference #5698
This creates a gbenchmark for cudf::strings::replace_re functions and the cudf::strings::replace_with_backrefs function. The benchmarks measures various sized rows as well as strings lengths. This PR also includes changes to source files for these 3 functions cleaning up the code and replacing device_vector usages with device_uvector and device_span.

[codecov]

Codecov Report

Merging #7541 (4ccedb6) into branch-0.19 (7871e7a) will increase coverage by 0.19%.
The diff coverage is 93.16%.

❗ Current head 4ccedb6 differs from pull request most recent head 9825ec8. Consider uploading reports for the commit 9825ec8 to get more accurate results

@@               Coverage Diff               @@
##           branch-0.19    #7541      +/-   ##
===============================================
+ Coverage        81.86%   82.05%   +0.19%     
===============================================
  Files              101      101              
  Lines            16884    17008     +124     
===============================================
+ Hits             13822    13956     +134     
+ Misses            3062     3052      -10     

Impacted Files	Coverage Δ
python/cudf/cudf/core/index.py	92.86% <ø> (ø)
python/cudf/cudf/core/series.py	91.33% <ø> (+0.55%)	⬆️
python/cudf/cudf/core/tools/datetimes.py	84.44% <ø> (ø)
python/cudf/cudf/utils/cudautils.py	50.38% <ø> (ø)
python/cudf/cudf/utils/dtypes.py	89.88% <ø> (+0.37%)	⬆️
python/dask_cudf/dask_cudf/io/orc.py	91.04% <ø> (+0.13%)	⬆️
python/cudf/cudf/core/column/numerical.py	94.83% <87.50%> (-0.20%)	⬇️
python/cudf/cudf/core/frame.py	89.00% <89.47%> (-0.02%)	⬇️
python/cudf/cudf/core/column/column.py	87.77% <90.00%> (+0.01%)	⬆️
python/cudf/cudf/core/column/decimal.py	92.75% <90.32%> (-2.12%)	⬇️
... and 19 more

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[harrism]

@gpucibot merge