snap: Add registration configuration option

snap/hooks/configure

@@ -22,4 +22,10 @@ then
     echo "Invalid 'federation' setting: ${federation_enabled}. Valid values are 'true' or 'false'"
 fi
 
+registration_enabled=$(snapctl get registration)
+if [ -n ${registration_enabled} -a \( "${registration_enabled}" != "true" -a "${registration_enabled}" != "false" \) ]
+then
+    echo "Invalid 'registration' setting: ${registration_enabled}. Valid values are 'true' or 'false'"
+fi
+
 exit 0

snap/local/set-environment

@@ -22,6 +22,12 @@ then
     export ROCKET_FEDERATION_ENABLED=${federation_enabled}
 fi
 
+registration_enabled="$(snapctl get registration)"
+if [ -n "${registration_enabled}" -a "${registration_enabled}" = "false" ]
+then
+    export ROCKET_REGISTRATION_DISABLED="true"
+fi
+
 export ROCKET_ENV="production"
 export ROCKET_DATABASE_PATH=${SNAP_DATA}