Add an outputless target for codegen

[iminlikewithyou]

i'm setting up GH Actions linting for my project, and it depends on the assets TypeScript file that Asphalt generates. since it runs on PRs, I don't want to upload assets to Roblox and I don't need to sync any files to Studio. I just need the codegen file to be created, the asset strings can be empty or placeholder strings.

this would also be nice for GitHub codespaces, where you just need to generate the codegen so it can be referenced in code and get proper linting, but don't need to actually upload or sync any files.

[iminlikewithyou]

for full context, this is what happens when syncing to target studio from the GitHub Action (to avoid syncing to the cloud)

not sure why this happens

[jackTabsCode]

for full context, this is what happens when syncing to target studio from the GitHub Action (to avoid syncing to the cloud) not sure why this happens

It happens because it's trying to locate your studio directory.

[iminlikewithyou]

yeah, couple days ago i used an env variable i found to set the studio directory on Linux so that it would work for CI. it would still be awesome if it didn't duplicate assets to an output directory when it's not necessary to do so