Add rule group query_offset to Prometheus Schema (#5265)

* Add rule group query_offset to Prometheus Schema

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: Juan BUSTOS <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

src/schemas/json/prometheus.rules.json

@@ -103,6 +103,10 @@
             "$ref": "#/definitions/duration",
             "description": "How often rules in the group are evaluated."
           },
+          "query_offset": {
+            "$ref": "#/definitions/duration",
+            "description": "Offset the rule evaluation timestamp of this particular group by the specified duration into the past."
+          },
           "labels": {
             "$ref": "#/definitions/labels",
             "description": "Labels to add or overwrite before storing the result for its rules. Labels defined in <rule> will override the key if it has a collision."

src/test/prometheus.rules/rules.json

@@ -5,6 +5,7 @@
         "severity": "critical"
       },
       "name": "my-group-name",
+      "query_offset": "0s",
       "rules": [
         {
           "alert": "InstanceDown",