Fr: better icloud document storage support

there are two things i found missing here.

first, add an iCloud Permissions option to the macos exporter. it should add the same entitlements as the ios version (eg,,, and

second, the default container identifier on the ios side is iCloud.$(CFBundleIdentifier). ideally this would use the base juce bundleIdentifier since $(CFBundleIdentifier) can be overridden in the ios/macos exporters.

this ended up being pretty easy: