refactor: use pre/post triggers for service-action naming

This is a bit more clear as the links aren't always idempotent and may have errors - this allows users to reconcile at what point a link may have failed so that they can take further action.

common-functions

@@ -453,6 +453,7 @@ service_link() {
   fi
 
   [[ -n $LINK ]] && dokku_log_fail "Already linked as $LINK"
+  plugn trigger service-action pre-link "$SERVICE" "$APP"
   touch "$LINKS_FILE"
   echo "$APP" >>"$LINKS_FILE"
   sort "$LINKS_FILE" -u -o "$LINKS_FILE"
@@ -465,8 +466,9 @@ service_link() {
     dokku docker-options:add "$APP" build,deploy,run "--link $SERVICE_NAME:$SERVICE_DNS_HOSTNAME"
   fi
   [[ -n "$SERVICE_QUERYSTRING" ]] && SERVICE_URL="${SERVICE_URL}?${SERVICE_QUERYSTRING}"
+  plugn trigger service-action post-link "$SERVICE" "$APP"
   config_set "$APP" "${ALIAS}_URL=$SERVICE_URL"
-  plugn trigger service-action link "$SERVICE" "$APP"
+  plugn trigger service-action post-link-complete "$SERVICE" "$APP"
 }
 
 service_linked_apps() {
@@ -772,6 +774,7 @@ service_unlink() {
   local SERVICE_DNS_HOSTNAME=$(service_dns_hostname "$SERVICE")
   local LINK=($(echo "$EXISTING_CONFIG" | grep "$SERVICE_URL" | cut -d: -f1)) || true
 
+  plugn trigger service-action pre-unlink "$SERVICE" "$APP"
   remove_from_links_file "$SERVICE" "$APP"
 
   if declare -f -F add_passed_docker_option >/dev/null; then
@@ -783,8 +786,9 @@ service_unlink() {
   fi
 
   [[ -z ${LINK[*]} ]] && dokku_log_fail "Not linked to app $APP"
+  plugn trigger service-action post-unlink "$SERVICE" "$APP"
   config_unset "$APP" "${LINK[*]}"
-  plugn trigger service-action unlink "$SERVICE" "$APP"
+  plugn trigger service-action post-unlink-complete "$SERVICE" "$APP"
 }
 
 service_version() {