[core] Store cardinality in the deletion vector meta

[Zouxxyy]

Purpose

Store cardinality in the deletion vector meta, new meta like this:

 1. f0: the data file name corresponding to this deletion vector.
 2. f1: the starting offset of this deletion vector in the index file.
 3. f2: the length of this deletion vector in the index file.
 4. cardinality: the number of deleted rows.

new:

cardinality: It can be used for optimizing count(*) on the dv table.

compatibility:

upgrate CommitMessageSerializer to version 5
upgrate DataSplit to version 4

Tests

API and Format

Documentation

[JingsongLi]

Can you explain the usage for them separately?

[JingsongLi]

+1