[Ideas] Review the necessity of all CBDB-specified GUCs, and clean up those useless or rarely used ones

[jianlirong]

Description

As discussed in #693, there are currently over 400 CBDB-specified GUCs, which makes it very difficult for a user to select the correct one and its corresponding value. We need to revisit all CBDB-specified GUCs and remove those that are redundant or seldom used.

At the end of the day, when developing a database, we should strive to minimize the difficulty for users to use it, rather than increasing it.

Use case/motivation

We want to reduce the number of CBDB-specified GUCs to a few dozen, focusing on those that are essential and frequently used.

Related issues

#693

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[my-ship-it]

Yes, there are too many GUCs, and it is hard to understand what GUCs to use. Maybe we could keep DEVELOPER_OPTIONS GUCs which are invisible to user, and reduce user visible GUCs.