Add heap-sensitive cache implementation

[Nashatyrev]

Now user has to adjust cache sizes explicitly in the config.
It would be convenient to have an option for the caches to adjust their sizes according to free JVM heap (based on SoftReference). However upper cache size bound still needs to be specified

[arsalankhalid]

I want to move on this, are there any updates here? @Nashatyrev
Could you give some suggestions for attacking this