Add Path commands (#280)

* Add Path command

* Add `path basename`

* Refactor operate into `mod`

* Add `path dirname`

* Add `path exists`

* Add `path expand`

* Remove Arc wrapper for args

* Add `path type`

* Add `path relative`

* Add `path parse`

* Add `path split`

* Add `path join`

* Fix errors after rebase

* Convert to Path in `operate`

* Fix table behavior in `path join`

* Use conditional import in `path parse`

* Fix missing cases for `path join`

* Update default_context.rs

* clippy

* Fix tests

* Fix tests

Co-authored-by: JT <547158+jntrnr@users.noreply.github.com>
Co-authored-by: JT <jonathan.d.turner@gmail.com>

crates/nu-command/src/default_context.rs

@@ -74,6 +74,20 @@ pub fn create_default_context() -> EngineState {
             Zip,
         };
 
+        // Path
+        bind_command! {
+            Path,
+            PathBasename,
+            PathDirname,
+            PathExists,
+            PathExpand,
+            PathJoin,
+            PathParse,
+            PathRelativeTo,
+            PathSplit,
+            PathType,
+        };
+
         // System
         bind_command! {
             Benchmark,