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/input/v1beta1.annotation-conversions.json

@@ -154,10 +154,22 @@
             "exclude": true
           },
           "mappings": {
-            "title": "service",
-            "text": "description",
-            "time": "timestamp",
-            "tags": "labels"
+            "title": {
+              "source": "field",
+              "value": "service"
+            },
+            "text": {
+              "source": "field",
+              "value": "description"
+            },
+            "time": {
+              "source": "field",
+              "value": "timestamp"
+            },
+            "tags": {
+              "source": "field",
+              "value": "labels"
+            }
           },
           "builtIn": 0,
           "type": "influxdb"
@@ -214,4 +226,4 @@
     },
     "links": []
   }
-} 
+}