Allow configurable LevelDB options

Is your feature request related to a problem? Please describe.

The current configuration for LevelDB creates too many files. It's possible to decrease the number of files by changing the CompactionTableSize on LevelDB. The large amount of files has a negative impact on our IT infrastructure.

Describe the solution you'd like

Level DB has some parameters that can be tweaked, such as WriteBufferSize, BlockSize, BlockCacheCapacity, CompactionTableSize, CompactionL0Trigger, and OpenFilesCacheCapacity. These values should be configurable through the config file.

Describe alternatives you've considered

I've tried running 'db dump', but it takes a long time to complete.

Additional context

I've implemented this feature here, without any kind of test. https://github.com/linkd-academy/neo-go/commit/8ca4a311c01f7627967bf6fe818083b02271bb96

Result with 5GB CompactionTableSize (may not be ideal, 1 GB could be better):

Changing some parameters made it run faster on my macOS. My computer was barely usable during synchronization.

Don't forget to add labels!

• enhancement