update outputs command to be directly usable by Rojo projects

[blake-mealey]

The outputs command currently dumps to a JSON file which is not directly usable by anything. The primary use case I see for the outputs file is for automated consumption by Rojo projects. Therefore, there should be a way to produce a file that is Rojo-supported.

Additionally, we may need to consider splitting place file uploads from the rest of the deployment phase (e.g. mantle prepare and mantle publish) so that we can avoid the chicken-and-egg problem here.

[blake-mealey]

After having implemented image & audio assets I'm actually questioning the use-case for this now. Since those game assets should be referenced via rbxgameasset://Type/name there is no need to access them in this manner. That said, maybe meshes will change things?

[blake-mealey]

Scratch the previous comment. Things like badges, passes, and products all need to be accessible in-game.

[blake-mealey]

Turns out Rojo does support raw JSON files like this already (see rojo-rbx/rojo#308).

I'm closing this in favour of:

• improve outputs format #132
• consider splitting infrastructure creation and place deployments into separate commands #134