Introduce tests for Daemon and Plugin

[Ransomwave]

Introducing standardized tests for Azul would be a very nice QoL addition to the project, especially considering the influx of new PRs.

Daemon tests

• Ensure it generates correct files in the correct structure
• Ensure it sends the correct data in the correct structure to the Plugin
• Ensure build generates the correct instance data
• Ensure push generates the correct instance data
• Ensure pack generates a correct sourcemap.json
• Ensure --rojo generates correct instance data, alongside --rojo-project another.project.json

Plugin tests

• Ensure it generates the correct instances from incoming data
• Ensure it sends the correct instance data to the Daemon
• Ensure it properly applies patches