Create a TruncateOperator

[dimberman]

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Since the current TruncateOperator is essentially a DropTableOperator, we will need to build a TruncateOperator from scratch.

A truncate operator should not delete a table. Rather, it should clear out all rows and leave the table empty.

Acceptance criteria:

• [ ] A TruncateOperator class that clears all rows without deleting the table
• [ ] A corresponding aql.truncate function the enacts the TruncateOperator
• [ ] A new set of tests for the described functionality

Example test:

@pytest.mark.integration
@pytest.mark.parametrize(
    "database_table_fixture",
    [
        {
            "database": Database.SQLITE,
            "file": File(DEFAULT_FILEPATH),
        },
        {
            "database": Database.POSTGRES,
            "file": File(DEFAULT_FILEPATH),
        },
        {
            "database": Database.BIGQUERY,
            "file": File(DEFAULT_FILEPATH),
        },
        {
            "database": Database.SNOWFLAKE,
            "file": File(DEFAULT_FILEPATH),
        },
    ],
    indirect=True,
    ids=["sqlite", "postgres", "bigquery", "snowflake"],
)
def test_truncate_with_table_metadata(database_table_fixture, sample_dag):
    """Test truncate operator for all databases."""
    database, test_table = database_table_fixture
    assert database.table_exists(test_table)

    @aql.dataframe
    def validate(df: pandas.DataFrame):
        assert len(df) == 0
    with sample_dag:
        aql.truncate(
            table=test_table,
        )
    test_utils.run_dag(sample_dag)

    assert database.table_exists(test_table)