Fix column reflection in SQLAlchemy 2.0

[littlebtc]

Running alembic revision --autogenerate with SQLAlchemy 2.0.23 and Alembic 1.12.1 with existing table will miss all columns, resulting in errors like that if you have any engine configuration related to columns:

sqlalchemy.exc.ConstraintColumnNotFoundError: Can't create KeysExpressionOrColumn on table 'table': no column named 'column' is present.

In my code with ReplacingMergeTree engine and order_by set, It crashes here as the parent.c is empty; after tracing the code, it seems that the Table is heavily refactored in SQLAlchemy 2.0, and internally it will use table.c to access the columns. This PR added .c clones to _make_from_standard, making the --autogenerate works for me.

I also hit #275, and I managed to bypass it by adding a patched patch_alembic_version in the env.py.

Checklist:

• Add tests that demonstrate the correct behavior of the change. Tests should fail without the change.
• Add or update relevant docs, in the docs folder and in code.
• Ensure PR doesn't contain untouched code reformatting: spaces, etc.
• Run flake8 and fix issues.
• Run pytest no tests failed. See https://clickhouse-sqlalchemy.readthedocs.io/en/latest/development.html.