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/snapshot_middleware/util.rs

@@ -41,3 +41,8 @@ where
             .with_context(|| format!("Path did not end in {}: {}", suffix, path.display()))
     }
 }
+
+// TEMP function until rojo 8.0, when it can be replaced with bool::default (aka false)
+pub fn emit_legacy_scripts_default() -> Option<bool> {
+    Some(true)
+}