[sc189175] Use cursors on PG queries

[Shylpx]

Resources

• Shortcut story

Changes

• ~Use export_timeout in OGR exports instead of the render timeout.~ -> https://github.com/CartoDB/CartoDB-SQL-API/pull/698
• Update PG formats based on streams (json, geojson, svg) , to use cursors.

[shortcut-integration[bot]]

This pull request has been linked to Shortcut Story #189175: SQL API OOM errors when exporting data.

[Shylpx]

After increasing servers' memory, the error disappear, so using cursors is not needed anymore: https://app.shortcut.com/cartoteam/story/189175/sql-api-oom-errors-when-exporting-data#activity-198251