Chore: Upgrade Go to 1.21.5 (#79329)

* bumping grafanas go version to 1.21.5

* adding how to upgrade go doc

* removing the whole ci-build and corresponding pipelines

* clarifying that we have to run make drone

* fixing starlark linter and removing unused code

* Adding note about enterprise

* trying to change the underyling image to avoid musl issues

* only need to golang one

scripts/drone/utils/images.star

@@ -8,9 +8,10 @@ load(
     "nodejs_version",
 )
 
+# "go" image can be switched back to golang:{}-alpine once this is resolved https://github.com/mattn/go-sqlite3/pull/1177#issuecomment-1849176090
 images = {
     "git": "alpine/git:2.40.1",
-    "go": "golang:{}-alpine".format(golang_version),
+    "go": "golang:{}-alpine3.18".format(golang_version),
     "node": "node:{}-alpine".format(nodejs_version),
     "cloudsdk": "google/cloud-sdk:431.0.0",
     "publish": "grafana/grafana-ci-deploy:1.3.3",