Airflow ClickHouse Plugin v1.0.0

[bryzgaloff]

This is a major update to the plugin:

• Major codebase refactoring, including:
  • Revised structure of the classes: implementations based on DB API 2.0 and Client.execute are strictly separated. DB API 2.0 is an extra now.
  • Refined tests structure.
  • Updated project structure.
• Full support of all clickhouse-driver features.
• Support for some versions of Airflow and Python is dropped.
• pandas extra is removed.
• Some unused code removed, e.g. Makefile.
• Migrated to pyproject.toml instead of setup.py.