Adds drop number of rows command (#1663)

* Fix access to columns with quoted names

* Add a drop number of rows from end of table

crates/nu-cli/tests/commands/mod.rs

@@ -5,6 +5,7 @@ mod cd;
 mod compact;
 mod cp;
 mod default;
+mod drop;
 mod each;
 mod edit;
 mod enter;