use custom date parser

A specialized date parser that can only handle ISO-8601 like dates
(2011-12-03T10:15:30.123Z or 2011-12-03T10:15:30+01:00) but does this
roughly 10 times faster than DateTimeFormatter and 5 times
faster than the FastDateParser of commons-lang3.

block-storage/src/main/java/org/lucares/pdb/map/PersistentMapDiskNode.java

@@ -7,9 +7,9 @@ import java.util.List;
 import java.util.stream.Collectors;
 
 import org.lucares.collections.LongList;
-import org.lucares.pdb.blockstorage.intsequence.VariableByteEncoder;
 import org.lucares.pdb.map.NodeEntry.ValueType;
 import org.lucares.utils.Preconditions;
+import org.lucares.utils.byteencoder.VariableByteEncoder;
 
 /**
  * <pre>