Pydiverse-pipedag

- Fix bug when Reading DECIMAL(precision, scale) columns to pandas task (precision was interpreted like for Float where
precision <= 24 leads to float32). Beware that ``isinstance(sa.Float(), sa.Numeric) == True``.

- Rework `TableReference` support:
* Rename `TableReference` to `ExternalTableReference`
* Add support for `ExternalTableReference` to point to tables in external (i.e. not managed by `pipedag`) schemas.
* Remove support for `ExternalTableReference` that points to table in schema of current stage. I.e. `ExternalTableReference` can only point to tables in external schemas.
- Support code based configuration (see create_basic_pipedag_config() in README.md example without config file and without docker-compose)
- Added NoBlobStore in case you don't want to provide a directory that is created or needs to exist
- Fix polars import in `pyproject.toml` when using OS X with rosetta2
- Bug fix ibm_db2 backend:
* input tables for SQL queries were not locked

- Fix bug where a `Task` that was declared lazy but provided a `Table` without a query string would always be cache valid.
- Improved documentation

- Update dependencies and remove some upper boundaries
- Polars dependency moved to >= 0.18.12 due to incompatible interface change
- Workaround for duckdb issue: https://github.com/duckdb/duckdb/issues/10322
- Workaround for prefect needing pytz dependency without declaring it on pypi

- Bug fix ibm_db2 backend:
* unspecified materialization_details was failing to load configuration
- Bug fixes for mssql backend:
* SELECT-INTO was invalid for keyword suffix labels: i.e. `SELECT 1 as prefix_FROM`
* Raw SQL statements changing database link of connection via `USE` was causing pipedag generated commands to fail

- increased metadata_version to 0.3.2 => please delete metadata with pipedag-manage when upgrading from <= 0.6.6 to >= 0.6.7
- Make separator customizable when splitting RawSql into statements.
- Add `DropNickname` for DB2 and drop nicknames when dropping schemas.
- Add debug function `materialize_table`.
- Update install instructions and dependencies to enable DB2 and mssql development on OS X with an `arm64` architecture.
- Update PR template
- Run `RUNSTATS` on every DB2 table after creation
- Add `materialization_details` as an option to `IBMDB2TableStore`. For now DB2 compression, DB2 table spaces are supported and Postgres `unlogged` tables are supported.
- For Postgres `unlogged` tables this is a breaking change. The `unlogged_tables` option does not exist anymore. Instead, use `materialization_details: __any__: unlogged: true`.

Workaround for known Problems:
- add materialization_details in configuration when using ibm_db2 database connection