Add camera permission for iOS 10 (#4565)

https://developer.apple.com/library/content/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html#//apple_ref/doc/uid/TP40009251-SW24

> Important: To protect user privacy, an iOS app linked on or after
> iOS 10.0, and which accesses the device’s camera, must statically
> declare the intent to do so. Include the NSCameraUsageDescription key
> in your app’s Info.plist file and provide a purpose string for this
> key. If your app attempts to access the device’s camera without a
> corresponding purpose string, your app exits.