rust frontend: support plan select * from x in stream

[skyzh]

We will convert select * from x in stream to StreamTableScan (not sure if this is correct).

Will finish this function:

impl ToStream for LogicalScan {
    fn to_stream(&self) -> PlanRef {
        todo!()
    }
}

[st1page]

I think the StreamMaterialize should not be in the to_stream of logicalScan but it should be at the top of the streaming plan, so it should not be in "LogicalScan::to_stream" but in PlanRoot::gen_create_mv_plan

[fuyufjh]

s/StreamMaterialize/StreamChain/ ?

[skyzh]

I'll implement stream source scan first, and later add chain.