Prometheus: Introduce prometheus backend library (#83952)

* Move files to prometheus-library

* refactor core prometheus to use prometheus-library

* modify client transport options

* mock

* have a type

* import aliases

* rename

* call the right method

* remove unrelated test from the library

* update codeowners

* go work sync

* update go.work.sum

* make swagger-clean && make openapi3-gen

* add promlib to makefile

* remove clilogger

* Export the function

* update unit test

* add prometheus_test.go

* fix mock type

* use mapUtil from grafana-plugin-sdk-go

pkg/promlib/converter/testdata/prom-string-frame.jsonc

@@ -0,0 +1,70 @@
+//  🌟 This was machine generated.  Do not edit. 🌟
+//  
+//  Frame[0] {
+//      "type": "timeseries-multi",
+//      "typeVersion": [
+//          0,
+//          0
+//      ],
+//      "custom": {
+//          "resultType": "string"
+//      }
+//  }
+//  Name: 
+//  Dimensions: 2 Fields by 1 Rows
+//  +-----------------------------------+----------------+
+//  | Name: Time                        | Name: Value    |
+//  | Labels:                           | Labels:        |
+//  | Type: []time.Time                 | Type: []string |
+//  +-----------------------------------+----------------+
+//  | 2022-05-04 16:02:19.104 +0000 UTC | example        |
+//  +-----------------------------------+----------------+
+//  
+//  
+//  🌟 This was machine generated.  Do not edit. 🌟
+{
+  "status": 200,
+  "frames": [
+    {
+      "schema": {
+        "meta": {
+          "type": "timeseries-multi",
+          "typeVersion": [
+            0,
+            0
+          ],
+          "custom": {
+            "resultType": "string"
+          }
+        },
+        "fields": [
+          {
+            "name": "Time",
+            "type": "time",
+            "typeInfo": {
+              "frame": "time.Time"
+            }
+          },
+          {
+            "name": "Value",
+            "type": "string",
+            "typeInfo": {
+              "frame": "string"
+            },
+            "labels": {}
+          }
+        ]
+      },
+      "data": {
+        "values": [
+          [
+            1651680139104
+          ],
+          [
+            "example"
+          ]
+        ]
+      }
+    }
+  ]
+}