Dev/new stats

[py-cyber]

Summary

This PR adds 6 new statistics to the DataStats class. These statistics help users understand their data better.

New Statistics

1. Interquartile Range — shows the spread of the middle 50% of numeric data
2. Coefficient of Variation — shows how much data varies compared to the average
3. Monotonicity — tells if data always goes up, always goes down, always the same, or neither
4. Jarque-Bera Statistic — tests if numeric data has a normal distribution
5. Entropy — measures how mixed categorical data is
6. Gini Coefficient — measures inequality in categorical data

Changes

1. Core

   Location: src/core/algorithms/statistics/
   Change: extended DataStats class with six new statistical methods. Enhanced ColumnStats data structure to store new statistics.

2. Python Bindings

   Location: src/python_bindings/statistics/
   Change: added pybind methods for all new statistics.

3. Tests

   Location: src/tests/unit/
   Change: implemented google-testing for new statistical methods.

   Location: src/python_bindings/
   Change: implemented Python integration tests for new statistical methods.

4. Examples

   Location: examples/basic/
   Change: Updated demonstration case to show usage of all new statistics.