feat: dataframe_serializer supports batching

[bednar]

Closes #291

Proposed Changes

1. The dataframe_serializer supports batching - serialize DataFrame rows in batches corresponding to batch_size.
2. Added an example how to import large DataFrame

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• pytest tests completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Merging #293 (b7070c2) into master (025e97e) will increase coverage by 0.11%.
The diff coverage is 97.93%.

@@            Coverage Diff             @@
##           master     #293      +/-   ##
==========================================
+ Coverage   92.38%   92.50%   +0.11%     
==========================================
  Files          27       27              
  Lines        2168     2189      +21     
==========================================
+ Hits         2003     2025      +22     
+ Misses        165      164       -1     

Impacted Files	Coverage Δ
...fluxdb_client/client/write/dataframe_serializer.py	98.01% <97.77%> (-0.77%)	⬇️
influxdb_client/client/write_api.py	99.06% <100.00%> (+<0.01%)	⬆️
influxdb_client/client/util/date_utils.py	96.29% <0.00%> (+7.40%)	⬆️

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