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

.github/workflows/pr-codeql-analysis-go.yml

@@ -26,7 +26,7 @@ jobs:
     - name: Set go version
       uses: actions/setup-go@v4
       with:
-        go-version: '1.21.3'
+        go-version: '1.21.5'
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL