Add primitive's usage examples in a form of Python notebooks

[artem-burashnikov]

This PR adds examples in a form of python notebooks.
The Left-hand side shows the source of the example, the right-hand side displays the resulting notebook.
Some of the examples got combined into a single notebook:

1. data_stats.py $\rightarrow$ Simple_Statistics.ipynb

2. mining_fd.py $\rightarrow$ Functional_Dependencies_Mining.ipynb

3. verifying_fd_afd.py $\rightarrow$ Approximate_and_Exact_Functional_Dependencies_Verification.ipynb

4. mining_afd.py $\rightarrow$ Approximate_Functional_Dependencies_Mining.ipynb

5. mining_sfd.py $\rightarrow$ Soft_Functional_Dependencies_Mining.ipynb

6. mining_ind.py $\rightarrow$ Inclusion_Dependencies_Mining.ipynb

7. mining_aind.py $\rightarrow$ Approximate_Inclusion_Dependencies_Mining.ipynb

8. verifying_ind_aind.py $\rightarrow$ Approximate_and_Exact_Inclusion_Dependencies_Verification.ipynb

9. mining_ucc.py $\rightarrow$ Unique_Column_Combinations_Mining.ipynb

10. mining_aucc.py $\rightarrow$ Appxoximate_Unique_Column_Combinations_Mining.ipynb