Revert the use of async cache to Caffeine (sync) cache

[pditommaso]

The use of with virtual threads causes with Caffeine local (sync) cache causes the pinning of the "carrier" thread due to the internal use of ConcurrentHashMap.

to prevent the pinning of the carrier thread, and resulting, performance degradation a workaround consists using the "async" version of Caffeine cache.

See here and here.

The goal of this issue is to revert the use of async cache once the issue of ConcurrentHashMap and virtual threads has been resolved in the Java runtime, implemented by this commit 9850c84.