Federation analyzer should federate the subquery when possible (#26)

* optimize_recursively should check the provider for subqueries

* Preserve the vec<provider>,use apply_subqueries

* Federate subtree in subquery

* clean up

* Rewrite federation as optimizer rule

* Revert "Rewrite federation as optimizer rule"

This reverts commit e0ff999.

* Keep federaion rule as analyzer rule, handle InSubquery federation

* Wrap a Projection plan when the entire Insubquery can be federated

* not run scalar_subquery_to_join and update scalar subquery handling

* Resolve outref federation provider

* clean up

* Include table reference created by subquery aliases

* Remove redundant clone

* Do not panic on ScanResult unwrap