Summary:
The `ybcSetupTargets` function builds BMS of required attributes and also uses the `YbDmlAppendTargetSystem` / `YbDmlAppendTargetRegular` function directly. Its reasonable to use BMS only.

**Note:**
The diff contains changes in the `PgSysTablePrefetcher` class. Because this class need to prefetch sys tables with the same target columns order like `ybcSetupTargets` produces. The `PgSysTablePrefetcher` class  must adjust the target order produces by the `ybcSetupTargets` function and not vise versa.

Also this diff removes necessity to read the `ybctid` field for the `pg_yb_catalog_version` table.
Jira: DB-14150

Test Plan: Jenkins

Reviewers: amartsinchyk, telgersma

Reviewed By: telgersma

Subscribers: yql

Tags: #jenkins-ready

Differential Revision: https://phorge.dev.yugabyte.com/D40090