Switch Manifest and Config File Format to nuon

[freepicheep]

Per #25, we are switching quiver project manifests, lockfiles, and global config from toml to nuon.

Changed

• BREAKING: The package manifest is now nupackage.nuon instead of nupackage.toml. The lockfile is also in nuon format. Existing projects must migrate:

  open nupackage.toml | to nuon --indent 2 | save -f nupackage.nuon
  rm nupackage.toml
  rm quiver.lock
  qv install

• BREAKING: The global Quiver config is now config.nuon. Navigate to your global quiver config dir and run the following to migrate:

    open config.toml | to nuon --indent 2 | save -f config.nuon
    rm config.toml
    rm quiver.lock
    qv install -g

• Quiver will warn users with migration instructions when a legacy nupackage.toml or config.toml is detected.

This closes #25