[Ideas] Remove Unused Files (concourse/*, hd-ci/*) After Cherry-Pick Completion

[tuhaihe]

Description

As part of the ongoing cherry-pick process from the Greenplum archive, we have identified two directories (concourse/ and hd-ci/*) that are no longer in use and will not be part of Cloudberry’s future development.

To maintain a cleaner codebase, I propose that we remove these directories and their files from the main repository after the cherry-pick process is complete.

I searched and found there are three places that need to be cleaned up:

- concourse/*
- hd-ci/*
- src/backend/gporca/concourse/*.yml

I just want to confirm if it would be good to proceed with this. Please share your thoughts or concerns. Your feedback is greatly appreciated!

Use case/motivation

No response

Related issues

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[tuhaihe]

Already removed these files via PR #920.