Read nextcloud versions from app's package.json

[ChristophWurst]

If an app targets an older Nextcloud server version it might be fine to use a deprecated or remove function/prop. Hence the package.json should be read and respected.

A possible format would be

{
    "nextcloud": {
        "min-version": "15.0.0",
        "max-version: 17.0.0"
}