Implement Syncback to support converting Roblox files to a Rojo project (#937)

This is a very large commit.
Consider checking the linked PR for more information.

crates/memofs/src/noop_backend.rs

@@ -26,6 +26,20 @@ impl VfsBackend for NoopBackend {
         Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
+    fn create_dir(&mut self, _path: &Path) -> io::Result<()> {
+        Err(io::Error::new(
+            io::ErrorKind::Other,
+            "NoopBackend doesn't do anything",
+        ))
+    }
+
+    fn create_dir_all(&mut self, _path: &Path) -> io::Result<()> {
+        Err(io::Error::new(
+            io::ErrorKind::Other,
+            "NoopBackend doesn't do anything",
+        ))
+    }
+
     fn remove_file(&mut self, _path: &Path) -> io::Result<()> {
         Err(io::Error::other("NoopBackend doesn't do anything"))
     }