Upgrades the included openhab-js version to 3.1.0, which uses the new caches from core (introduced in https://github.com/openhab/openhab-core/pull/2887) and provides many doc improvements. Removes the SharedCache from the addon because this functionality is now provided by core (see https://github.com/openhab/openhab-core/pull/2887). Signed-off-by: Florian Hotze <florianh_dev@icloud.com>