[v11.3.x] CI: Support more version formats in publishing (#94750)

CI: Support more version formats in publishing (#94575)

* cleanup dead code
* add tests and rewrite publish grafanacom steps to reuse
* add pkg/build tests; don't upload CDN assets on grafana releases

(cherry picked from commit 7a2edd35d5)

pkg/build/cmd/flags.go

@@ -16,37 +16,15 @@ var (
 		Usage: "The edition of Grafana to build (oss or enterprise)",
 		Value: "oss",
 	}
-	variantsFlag = cli.StringFlag{
-		Name:  "variants",
-		Usage: "Comma-separated list of variants to build",
-	}
 	triesFlag = cli.IntFlag{
 		Name:  "tries",
 		Usage: "Specify number of tries before failing",
 		Value: 1,
 	}
-	noInstallDepsFlag = cli.BoolFlag{
-		Name:  "no-install-deps",
-		Usage: "Don't install dependencies",
-	}
-	signingAdminFlag = cli.BoolFlag{
-		Name:  "signing-admin",
-		Usage: "Use manifest signing admin API endpoint?",
-	}
-	signFlag = cli.BoolFlag{
-		Name:  "sign",
-		Usage: "Enable plug-in signing (you must set GRAFANA_API_KEY)",
-	}
 	dryRunFlag = cli.BoolFlag{
 		Name:  "dry-run",
 		Usage: "Only simulate actions",
 	}
-	gitHubTokenFlag = cli.StringFlag{
-		Name:    "github-token",
-		Value:   "",
-		EnvVars: []string{"GITHUB_TOKEN"},
-		Usage:   "GitHub token",
-	}
 	tagFlag = cli.StringFlag{
 		Name:  "tag",
 		Usage: "Grafana version tag",