support for exporting data to client or S3

[WenyXu]

What type of enhancement is this?

User experience

What does the enhancement do?

Our data export tool currently sends a COPY DATABASE ... TO statement to the frontend node, resulting in the exported data being saved only on the server's (frontend node's) local disk, regardless of where the command is executed.

We should enhance the tool to support exporting data directly to the client or an S3 bucket.

See also #5136

Implementation challenges

No response