macOS API calls must be thread safe

[tresf]

Per hidapi, macOS HID API calls MUST be executed on the same thread to be safe:

• Documentation: add multi-threading notes libusb/hidapi#45
• Potential solution to MacOS hid_init/hid_exit issue libusb/hidapi#666
• Crash when calling enumerate from different threads (not simultaneously) trezor/cython-hidapi#148

Currently, separate threads interacting with a HID devices on macOS, the entire JVM will crash. This can actually be caused by same-thread execution due to this automatic shutdown hook.

• hid4java Device Scanner crashes on mac after 30-40 seconds #37
• Workaround: qzind/tray@5e45845

hid4java/src/main/java/org/hid4java/HidServices.java

Lines 90 to 99 in 672f0a7

	if (hidServicesSpecification.isAutoShutdown()) {
	// Ensure we release resources during shutdown
	Runtime.getRuntime().addShutdownHook(
	new Thread() {
	@Override
	public void run() {
	shutdown();
	}
	});
	}

Despite this being an upstream issue, Java has some ways of thread pooling so that we can manage this downstream until upstream has a permanent fix.

@Vzor- will be submitting a PR which references this issue with a proposed downstream threading solution.