Set bundle ID to “org.readium.SDKLauncher.iOS”

And set the release build configuration to sign the app with the Readium foundations enterprise iOS certificate for distribution to testers.

When creating the enterprise certificate the bundle ID _org.readium.SDKLauncher-iOS_ was not allowed/available so I had to go with something else so I made it __org.readium.SDKLauncher.iOS__

This change will cause the build to fail when using the release configuration unless you have the enterprise certificate installed on your machine. This may not be ideal so I am putting this up in case anyone wants to suggest a different approach to handle this, I was unsure if it would be wise to create a separate configuration or anything like that. Debug configurations should still work as they have always.