[package outputs] add --outputs flag to devbox add, and save in config

[savil]

Summary

Enables devbox add <package-name> --outputs <output-name> to add an outputs field to the config for that package.

The next PR will hook up reading this outputs field from the config, and changing how we generate the flake.nix to match this outputs field.

How was it tested?

augmented unit tests

> devbox add prometheus --outputs out,cli
Info: Adding package "prometheus@latest" to devbox.json
Info: Added outputs out, cli to package prometheus@latest



> git diff devbox.json
diff --git a/devbox.json b/devbox.json
index 224072bc..f1a0c59c 100644
--- a/devbox.json
+++ b/devbox.json
@@ -3,6 +3,10 @@
     "go":                          "latest",
     "runx:golangci/golangci-lint": "latest",
     "runx:mvdan/gofumpt":          "latest",
+    "prometheus": {
+      "version": "latest",
+      "outputs": ["out", "cli"],
+    },
   },
   "env": {
     "GOENV": "off",

[savil]

Current dependencies on/for this PR:

• main
  • PR [package outputs] add --outputs flag to devbox add, and save in config #1707 👈
    • PR [package outputs] generate buildInputs for package-outputs in flake #1721

This stack of pull requests is managed by Graphite.

[savil]

@gcurtis ping