Prune command: add option for all packages as scopes

[nightknighto]

Goals

1. turbo prune command doesn't have an option to specify all packages.
2. To select all packages, they must all be written manually.
3. There should be either a special value or a flag to select all packages automatically.

Non-goals

No response

Background

I have a monorepo with turborepo. I am trying to make a dockerized workflow of testing all the packages. Each package has npm test, and I run all tests from the root. In the Dockerfile, I want to copy all package.json files of all the monorepo into the image, npm install, then copy the rest of the project. turbo prune command is great with the --docker flag, however it forces to specify a scope. I need all packages, so I am forced to write the names of all packages in the command. I would love a way for it to automatically do it for all packages.

Proposal

Any of these works:
1- Add a special value for scope: all, .
2- Add a flag: --all

These should be equivalent to specifying all packages as context.