Log extension module loading errors other than ModuleNotFoundException at ERROR

ExtensionAddHandler is converting all ModuleLoadExceptions to OFE, which means they only get logged at DEBUG post-boot.

This can be more precise – a ModuleNotFoundException is likely a user error (wrong module name) and thus should get the current treatment. But other ModuleLoadExceptions likely indicate some issue with the server installation and deserve ERROR level logging. Solution is to wrap those in a RuntimeException instead of an OFE.