Cherry-pick commits from GPDB, for psycopg2

[reshke]

The main goal is to upgrade python management scripts to use psycopg2. In GPDB, this was done by b5920e061b4a347523899838f6027c947107306e

To achieve this, I have actually cherry-picked more commits from [1]. It was done to reduce conflicts-resolution job pain.

This is WIP PR to get initial feedback. I need to double check my work (if these is any conflict-resolving related bugs), but for our deployment this works fine.

[1] https://github.com/greenplum-db/gpdb-archive/commits/main/gpMgmt/bin/gpexpand

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0 out of 3 committers have signed the CLA.

:x: Annu149
:x: shrakesh
:x: kainwen
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[edespino]

@reshke I believe this is a supporting PR that you may want to consider for this work: https://github.com/greenplum-db/gpdb-archive/commit/6f9d85b8bb571ed4195aaf05de4fba80cc0b9e7a

[jiaqizho]

Fix the CI pls :)