Is it possible to add packages defined under repositories?

Is it possible somehow to to let satis cache this types of packages?

```
"repositories": [
{
"type": "package",
"package": {
"name": "components/placeholdersjs",
"type": "component",
"version": "4.0.1",
"dist": {
"url": "https://github.com/jamesallardice/Placeholders.js/archive/v4.0.1.zip",
"type": "zip"
},
"extra": {
"component": {
"scripts": [
"dist/placeholders.min.js",
"dist/placeholders.jquery.min.js"
]
}
}
}
}
]
```

No files, tests, or entry points are named. Start by reviewing how Satis handles Composer repositories and package definitions, then clarify the expected caching behavior for the shown package repository and identify coverage needed for that behavior.

Written by the indexing model from the issue text.