feat: http server and cmd crate etc. (#15)

* feat: adds cmd crate and http server

* feat: impl sql http handler

* feat: convert all arrow array types

* feat: adds query test

* feat: adds test for datanode

* fix: format

* feat: refactor state.rs

* feat: adds collect test

* fix: by code review

* fix: style

src/sql/src/dialect.rs

@@ -1 +1,3 @@
 // todo(hl) wrap sqlparser dialects
+
+pub use sqlparser::dialect::{Dialect, GenericDialect};