postgres: Support creating partitioned tables

Hi!

The TableCreateStatement does not support creating partitioned tables.

1. Create partitioned table statement

CREATE TABLE measurement (
    city_id         int not null,
    logdate         date not null,
) PARTITION BY RANGE (logdate);

2. Create partition statement

CREATE TABLE measurement_y2006m02 PARTITION OF measurement
    FOR VALUES FROM ('2006-02-01') TO ('2006-03-01');

Reasoning:

• I see this feature request plus #1922 as the necessary features to make SeaORM + Postgres work well with huge amounts of data.

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Thanks

Start with the TableCreateStatement API linked in the issue and compare it with PostgreSQL's partitioning documentation. Define how it should represent partitioned table creation and partition creation, then verify that the generated SQL matches the two examples in the issue.