Add RunContext support for script outputs (#765)

Resolves #667

This PR:

- Introduces a new field in the project file: `scriptType` which has the
default value of `Class` (in parity with previous versions), but can
also be `RunContext`.
- This is then passed to `InstanceContext` from the `Project` struct.
- This then changes the RunContext in the lua `snapshot_middleware`

---------

Co-authored-by: Micah <dekkonot@rocketmail.com>

src/serve_session.rs

@@ -123,7 +123,8 @@ impl ServeSession {
 
         let root_id = tree.get_root_id();
 
-        let instance_context = InstanceContext::default();
+        let instance_context =
+            InstanceContext::with_emit_legacy_scripts(root_project.emit_legacy_scripts);
 
         log::trace!("Generating snapshot of instances from VFS");
         let snapshot = snapshot_from_vfs(&instance_context, &vfs, start_path)?;