Suricata

Add initial support to PostgreSQL's CopyOut mode, in which a backend will send 0 or more CopyData [Out] messages to a frontend, in response to a COPY TO STDOUT statement from a simple query (happens in extended mode/ subprotocol, too, although extended query mode isn't covered by the pgsql app-layer yet).

PostgreSQL's protocol has a so called Copy subprotocol.

The COPY operations can be split into three different modes (cf https://www.postgresql.org/docs/13/protocol-flow.html#PROTOCOL-COPY):
- Copy-In mode - high-speed bulk data transfer to the server
- Copy-Out mode - high-speed bulk data transfer from the server
- Copy-Both - high-speed bulk data transfer to and from the server