query command with json, web, xml (#870)

* query command with json, web, xml

* query xml now working

* clippy

* comment out web tests

* Initial work on query web

For now we can query everything except tables

* Support for querying tables

Now we can query multiple tables just like before, now the only thing
missing is the test coverage

* finish off

* comment out web test

Co-authored-by: Luccas Mateus de Medeiros Gomes <luccasmmg@gmail.com>

crates/nu_plugin_query/src/main.rs

@@ -0,0 +1,6 @@
+use nu_plugin::{serve_plugin, CapnpSerializer};
+use nu_plugin_query::Query;
+
+fn main() {
+    serve_plugin(&mut Query {}, CapnpSerializer {})
+}