String type support for packages, list, and params fields

[Cugatay]

Currently, packages, list, and params fields only support a list type. Instinct of writing package and parameter lists as string and split packages/params with space was irresistable when I tested the experience of configuration. So, we'll support additionally string types too for those fields.

Sorry for the incomprehensibility in my writing style, if there is any. Haven't been sleeping for 20 hours, and this is a little a lot for me 🥴

[Cugatay]

Let me give you an example here:

{
  type: "install",
  packages: ["this", "is", "really", "annoying", "to", "write"],
  params: ["--and", "--also", "--this", "--one", "--too"],
}

This is the thing that I want to solve. Here is the solved version:

{
  type: "install",
  packages: "this is really amazing to write",
  params: "--and --this --one --is --comfortable --too",
}