[jsscripting] Cache openhab-js injection to improve performance (#14135)

[jsscripting] Cache openhab-js injection to improve performance (#14135)

* [jsscripting] Extend comments for wraprequire
* [jsscripting] Enable openhab-js caching to improve performance

On my dev system (which I guess is much more powerful than most openHAB servers), cached openhab-js injection takes 100-200 ms.
openhab-js injection from file system takes about 1000 ms.

* [jsscripting] Update configuration language
* [jsscripting] Upgrade openhab-js version to 3.2.1 for required webpack changes

Documentation updates will follow in another PR to keep this one clean.

Signed-off-by: Florian Hotze <florianh_dev@icloud.com>