rename plist file for AppContainer settings

[p-x9]

Renamed settings file from settings.plist to com.p-x9.AppContainer.settings.plist.

closes #38

Warning
Information on the currently active container will be lost.
This change will not cause any loss of information for containers other than the currently active container.

If you want to carry over information created in previous versions, you will need to rename the file as follows.

let fileManager = FileManager.default

let home = NSHomeDirectory()
// If you are using it for App Group, change as follows
// let home = fileManager.containerURL(forSecurityApplicationGroupIdentifier: "YOUR APP GROUP IDENTIFIER")!.absoluteString

let libraryPath = home + "/Library"

let oldPath = libraryPath + "/settings.plist"
let newPath = libraryPath + "/com.p-x9.AppContainer.settings.plist"

guard fileManager.fileExists(atPath: oldPath) else { return }
try? fileManager.moveItem(atPath: oldPath, toPath: newPath)