[Enhancement]: Support sqlalchemy plugin should fully support MySQL

[PaleNeutron]

Description

I'm the author of sqlalchemy-oceanbase . As I mentioned in README, there still a gap in ddl between official MySQL and OceanBase dialect.

Please consider make my code officially supported.

[Linnore]

The recently added plugin pyobsql contains the oceanbase dialect for sqlalchemy now, but it's not in the standard sqlalchemy dialect package structure: https://github.com/sqlalchemy/sqlalchemy/blob/main/README.dialects.rst

Currently the oceanbase dialect can be used in process:

from importlib.util import find_spec

from sqlalchemy.dialects import registry

def _register_oceanbase_dialects() -> bool:
    if find_spec("pyobsql.schema.dialect"):
        registry.register("mysql.oceanbase", "pyobsql.schema.dialect", "OceanBaseDialect")
        return True
    else:
        return False

@oceanbase-admin
Maybe the oceanbase team can maintain a separate plugin for sqlalchemy's dialect in mysql compatible mode by just restructure a bit pyobsql into sqlalchemy-oceanbase? In this way, any package using alembic for their database migration and sqlalchemy for their ORM can use Oceanbase's Mysql Compatible mode as the backend.