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