Alerting: Add recording rules to ruler API and validation (#87779)

* Read path, main API

* Define record field for incoming requests

* Refactor several alerting specific validators into two paths

* Refactor validateCondition actually contain all the condition validation logic

* Move condition validation inside rule path

* Validators for recording rules

* Wire feature flag through to validators

* Test for accepting a valid recording rule

* Tests for negative case, no UID

* Test for ignoring alerting fields

* Build conditions based on recording rules as well

* Regenerate swagger docs

* Fix CRUD test to cover the right thing

* Re-generate swagger docs with backdated v0.30.2 version

* Regenerate base spec

* Regenerate ngalert specs

* Regenerate top level specs

* Comment and rename

* Return struct instead of modifying ref

pkg/tests/api/alerting/api_alertmanager_test.go

@@ -908,8 +908,9 @@ func TestIntegrationAlertRuleCRUD(t *testing.T) {
 						Annotations: map[string]string{"annotation1": "val1"},
 					},
 					GrafanaManagedAlert: &apimodels.PostableGrafanaRule{
-						Title: "AlwaysFiring",
-						Data:  []apimodels.AlertQuery{},
+						Title:     "AlwaysFiring",
+						Condition: "A",
+						Data:      []apimodels.AlertQuery{},
 					},
 				},
 				expectedMessage: "invalid rule specification at index [0]: invalid alert rule: no queries or expressions are found",