confd: use keyless services list, allow duplicate PIDs

Multiple services can have PID 0 when stopped/done, making PID
unsuitable as a unique key. There could also be multiple services with
the same name (I would assume?).

Signed-off-by: Richard Alpe <[email protected]>

Author: rical

src/confd/yang/confd/infix-system.yang

@@ -423,7 +423,6 @@ module infix-system {
       config false;
 
       list service {
-        key "pid";
         description "Tracked system service processes.";
 
         leaf pid {