Optional compaction after pruning

[yontyon]

We add an option to invoke rocksb compaction explicitly after pruning

[dartdart26]

Do we want to merge this in 0.11.x at that stage? @teoparvanov?

[teoparvanov]

Do we want to merge this in 0.11.x at that stage? @teoparvanov?

Hi @dartdart26 and @yontyon, yes, we would merge this, once we:

• make sure it improves the "responsiveness" of pruning
• it has been validated by system testing (using a custom build with the current changes).