[cache] Change implementation to the new access-tracking cache in core

[florian-h05]

With the addition of both a privateCache (per script identifier, useful for sharing timers) and a sharedCache (shared across all scripts from all languages) in https://github.com/openhab/openhab-core/pull/2887, we have to update our implementation of cache.

Backward compatibility must be kept!!

After we have a solution here, we can remove the SharedCache from JS Scripting.

My proposal is:

• for the current methods of cache:
  • check if the new caches from core are available
  • if they are available, log a deprecation warning and use the shared cache from core instead of the addon‘s shared cache implementation so that we can remove SharedCache from the addon
  • if they are not available (means the library runs on an „old“ openHAB version), do nothing and keep the current behaviour
• add a private property to cache to allow access to the private cache
• add a shared property to cache to allow access to the shared cache

@rkoshak @digitaldan @jpg0 WDYT?

[florian-h05]

@wborn FYI: Before removing the SharedCache from the JS Scripting add-on, we/I have to change the implementation of the cache in the helper library.

[rkoshak]

Sounds good to me.