Version 0.2: Include Base Scriptable Objects Items

This adds Scriptable Objects for Events and Variables. This is a redistribution of: https://gitlab.com/TwoScoopGames/two-scoop-games-scriptable-objects/tree/master/Assets/TwoScoopGames/Events and https://gitlab.com/TwoScoopGames/two-scoop-games-scriptable-objects/tree/master/Assets/TwoScoopGames/Variables