Add support for selecting a different bundle

[bpisano]

This PR adds support for selecting a different bundle instead of always using the main bundle when generating acknowledgements. The bundle parameter is optional and default to the main bundle to keep the simple syntax of Acknowledgements.all().

if let bundle = Bundle(identifier: "my.bundle") {
    let ack = Acknowledgements.all(in: bundle)
}

I updated the documentation of the .all() function.

I also updated the AcknowledgementsList component with the same bundle parameter.

struct ContentView: View {
    let bundle: Bundle

    var body: some View {
        AcknowledgementsList(bundle: bundle)
    }
}

Let me know if you have any comment. Thanks for this great package!

[MartinP7r]

Thank you very much for the addition!