Add InstanceMetadata builder (#269)

* Add InstanceMetadata builder, with context field for globbing

* Revert snapshot changes

* Port snapshot functions to InstanceMetadata builder-ish pattern

* Remove IgnoreGlob struct

* Elide lifetime

src/snapshot_middleware/rbxmx.rs

@@ -38,11 +38,11 @@ impl SnapshotMiddleware for SnapshotRbxmx {
         if children.len() == 1 {
             let snapshot = InstanceSnapshot::from_tree(&temp_tree, children[0])
                 .name(instance_name)
-                .metadata(InstanceMetadata {
-                    instigating_source: Some(entry.path().to_path_buf().into()),
-                    relevant_paths: vec![entry.path().to_path_buf()],
-                    ..Default::default()
-                });
+                .metadata(
+                    InstanceMetadata::new()
+                        .instigating_source(entry.path())
+                        .relevant_paths(vec![entry.path().to_path_buf()]),
+                );
 
             Ok(Some(snapshot))
         } else {