Add `AnyNestedCondition` which can be used to create a logical 'or' of
other conditions contained on nested classes. For example:

	static class OnJndiOrProperty extends AnyNestedCondition {

		@ConditionalOnJndi()
		static class OnJndi {
		}

		@ConditionalOnProperty("something")
		static class OnProperty {
		}

	}

Fixes gh-1490