REORG: server: move alert traces in parse_server

REORG: server: move alert traces in parse_server

Move every ha_alert calls in parsing functions into parse_server.
Parsing functions now support a pointer-to-string argument which will be
allocated with an error message if needed via memprintf.

parse_server has then the responsibility to display errors with ha_alert.

This is groundwork for dynamic server. No traces should be printed on
stderr as a response to a cli command. cli_err will replace ha_alert in
this case.