Pyroscope: add public catalog description (#74630)

* Add readme

* Fix wrong link

* Update public/app/plugins/datasource/grafana-pyroscope-datasource/README.md

Co-authored-by: Dmitry Filimonov <dmitry.filimonov@grafana.com>

* Prettier fix

* Update plugins test

* Prettier fix

* updateSnapshotFlag = false

---------

Co-authored-by: Dmitry Filimonov <dmitry.filimonov@grafana.com>

pkg/tests/api/plugins/data/expectedListResp.json

@@ -675,7 +675,7 @@
       "links": [
         {
           "name": "GitHub Project",
-          "url": "https://github.com/grafana/phlare"
+          "url": "https://github.com/grafana/pyroscope"
         }
       ],
       "logos": {
@@ -1896,4 +1896,4 @@
     "signatureOrg": "",
     "angularDetected": false
   }
-]
+]