[Generator] Create a Generator plugin

A `Generator` is a mechanic that produces an `Output` over time, optionally consumes an `Input`

```ts
interface GeneratorDefinition {
id: string
output: Output | Output[]
conditions?: Condition | Condition[]
input?: Input | Input[]
}

```
interface GeneratorState {
isActive: boolean
}

## TODO
- How to deal when you cannot consume the input, does it turn off or not produce/consume that tick?
- Currently outputs don't have support for being applied fractionally over time, which would be needed for this plugin. We could add something like `fracture(fraction: number)` next to `modify()`. Since all input and output is handled through the engine, you could update `engine.produce()` to add a fraction. I think that is fine for now as it is always a linear scaling fraction
- This would work for now, but not when we have complex outputs that require functions to calculate their `amount`, which is always static now.

## Other
- This is similar to a previous mechanic I had designed called [Boosters](https://123ishatest.github.io/igt-docs/docs/tools/boosters), which are more focused on modifiers
- This is also similar to another mechanic call [Actions](https://123ishatest.github.io/igt-docs/docs/tools/actions), but those are transactions after time has elapsed

But it is probably best to keep them separated into different plugins!