Batch replace

[ppalex7]

New method that produces query like:

DECLARE $batch AS List<Struct<p1:Int64, p2:Int32? /* ... */>>;
REPLACE INTO `table` SELECT p1 AS `field1`, p2 AS `field2` /* , ... */ AS_TABLE($batch);

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

There is no convenient method to save multiple TableRecords if some of them already exists in the table.
You needed to manually process each record with ReplaceSetStep or separate insert and update queries.

Issue Number: N/A

What is the new behavior?

Just call batchReplace for prepared TableRecords.

        dsl.batchReplace(records)
                .execute();

Other information

Implementation is based on the code example from https://st.yandex-team.ru/YDBREQUESTS-7135#6995b34de0b1c77c03452994