GONRG-6991: add variables for Reservoir

provider/partition-gc/bootstrap/data_gc.sh

@@ -36,6 +36,10 @@ generate_post_data_gc() {
       "sensitive": false,
       "value": "[${DATA_PARTITION_ID},${DATA_PARTITION_ID}]"
     },
+    "reservoir-connection": {
+      "sensitive": true,
+      "value": "RESERVOIR_POSTGRES_CONN_STRING_OSDU"
+    },
     "elasticsearch.host": {
       "sensitive": true,
       "value": "ELASTIC_HOST_${DATA_PARTITION_ID_UPPER}"