Add fn scan for sql dbs

[GG2002]

I‘ve noticed that SQLite has impl scan fn, while MYSQL, PostgreSQL, D1, and SurrealDB have not yet impl it. Since they are all SQL dbs (actually, I'm not quite sure if SurrealDB is SQL db), I thought the operation they perform should be similiar.

I'd like to add scan fn to these dbs as well. Could anyone give me some advice?

[Xuanwo]

I prefer to refactor #3639 first so we have a more solid base for adding more services.

Current design requires us to list all keys at once.