Makes rippled configurable to support deletion of all data in its key-value
store (nodestore) and ledger and transaction SQLite databases based on
validated ledger sequence numbers. All records from a specified ledger
and forward shall remain available in the key-value store and SQLite, and
all data prior to that specific ledger may be deleted.
Additionally, the administrator may require that an RPC command be
executed to enable deletion. This is to align data deletion with local
policy.
This new factory is intended for benchmarking against the existing RocksDBFactory and has the following differences.
* Does not use BatchWriter
* Disables WAL for writes to memtable
* Uses a hash index in blocks
* Uses RocksDB OptimizeFor… functions
See Benchmarks.md for further discussion of some of the issues raised by investigation of RocksDB performance.
