Parallel ledger loader & I/O performance improvements:

- Only duplicate records from archive to writable during online_delete.
- Log duration of nodestore reads.
- Include nodestore counters in perf_log output.
- Remove gratuitous nodestore activity counting.
- Report initial sync duration in server_info and perfLog.
- Report state_accounting in perfLog.
- Make state_accounting durations more accurate.
- Parallel ledger loader.
- Config parameter to load ledgers on start.

src/ripple/nodestore/impl/DatabaseNodeImp.cpp

@@ -47,7 +47,8 @@ std::shared_ptr<NodeObject>
 DatabaseNodeImp::fetchNodeObject(
     uint256 const& hash,
     std::uint32_t,
-    FetchReport& fetchReport)
+    FetchReport& fetchReport,
+    bool duplicate)
 {
     std::shared_ptr<NodeObject> nodeObject{
         cache_ ? cache_->fetch(hash) : nullptr};
@@ -70,13 +71,8 @@ DatabaseNodeImp::fetchNodeObject(
         switch (status)
         {
             case ok:
-                ++fetchHitCount_;
-                if (nodeObject)
-                {
-                    fetchSz_ += nodeObject->getData().size();
-                    if (cache_)
-                        cache_->canonicalize_replace_client(hash, nodeObject);
-                }
+                if (nodeObject && cache_)
+                    cache_->canonicalize_replace_client(hash, nodeObject);
                 break;
             case notFound:
                 break;