Router can not recognize query type "view"

After I set up the materialized plugin for broker and overlord, I send the some query to router which has the query type "view". However I got the some message like unrecognized query type.

### 0.20.3

### Description
Materialized plugin is very useful in my work, It accelerate the slow query from minitues to seconds.I think it's necessary to add support for query type view. It is unhandy to send query to broker instead of router. Especially when I want to use jdbc.

Start by reproducing the materialized-plugin query with type "view" through the router on the reported 0.20.3 setup, then trace where the router rejects unrecognized query types. Done means the router accepts and handles this query type, with a regression test covering the request path.

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