Schema v2: Move annotation mappings out of legacyOptions (#114721)

* Add mappings property to v2(alpha/beta)1

* Mappings convetions

* OpenAPI spec

* fe annotaations mapping

* Update snapshots

* v2->v1 conversion

* fix tests

---------

Co-authored-by: Haris Rozajac <haris.rozajac12@gmail.com>

apps/dashboard/pkg/migration/conversion/testdata/output/v1beta1.annotation-conversions.v2beta1.json

@@ -224,13 +224,25 @@
               3
             ]
           },
-          "legacyOptions": {
-            "mappings": {
-              "tags": "labels",
-              "text": "description",
-              "time": "timestamp",
-              "title": "service"
+          "mappings": {
+            "tags": {
+              "source": "field",
+              "value": "labels"
             },
+            "text": {
+              "source": "field",
+              "value": "description"
+            },
+            "time": {
+              "source": "field",
+              "value": "timestamp"
+            },
+            "title": {
+              "source": "field",
+              "value": "service"
+            }
+          },
+          "legacyOptions": {
             "type": "influxdb"
           }
         }