Restructure tree of sources

README.md

doctest/readme_doctests.py

examples/networkdisk-attribute_data.py

examples/networkdisk-independent_data.py

examples/networkdisk-one_table.py

examples/networkdisk-rich-with-helper.py

examples/networkdisk-shared_data.py

examples/quickstart-tuto.py

querybuilder/__init__.py

querybuilder/atoms/__init__.py

querybuilder/atoms/atoms.py

querybuilder/atoms/clauses.py

querybuilder/atoms/columns.py

querybuilder/atoms/constraints.py

querybuilder/atoms/relations.py

querybuilder/atoms/schemas.py

querybuilder/classes/__init__.py

querybuilder/drivers/postgres/__init__.py

querybuilder/drivers/postgres/tokenizer.py

querybuilder/drivers/sql/connector.py