Glue: Add DB migration & support provisioning for user-defined correlations config (#55560)

* Allow provisioning correlation config

* Simplify code

* Fix reading correlations test

* Fix linting errors

* Fix linting errors

* remove simpleJson

* Clean up

* Fix tests

* Update swagger docs

* Fix linting

* Fix linting

* Clean up swagger definitions

Co-authored-by: Elfo404 <me@giordanoricci.com>

devenv/datasources.yaml

@@ -52,6 +52,7 @@ datasources:
       implementation: prometheus
 
   - name: gdev-prometheus
+    uid: gdev-prometheus
     type: prometheus
     access: proxy
     url: http://localhost:9090
@@ -237,6 +238,13 @@ datasources:
       - targetUID: gdev-zipkin
         label: "Zipkin traces"
         description: "Related traces stored in Zipkin"
+      - targetUID: gdev-prometheus
+        label: "Logs to metrics"
+        description: "Related metrics stored in Prometheus"
+        config:
+          target:
+            expr: "{ job=\"test\" }"
+          field: "labels"
     jsonData:
       manageAlerts: false
       derivedFields: