Add guide page to actions when there's no workflows (#28145)

Before:

![image](https://github.com/go-gitea/gitea/assets/18380374/599d40c1-9b8d-4189-9286-c9c36fb780dd)

After:

![image](https://github.com/go-gitea/gitea/assets/18380374/848a73d1-aaec-478f-93a7-adcc7ee18907)

options/locale/locale_en-US.ini

@@ -3529,6 +3529,9 @@ runs.status = Status
 runs.actors_no_select = All actors
 runs.status_no_select = All status
 runs.no_results = No results matched.
+runs.no_workflows = There are no workflows yet.
+runs.no_workflows.quick_start = Don't know how to start with Gitea Action? See <a target="_blank" rel="noopener noreferrer" href="%s">the quick start guide</a>.
+runs.no_workflows.documentation = For more information on the Gitea Action, see <a target="_blank" rel="noopener noreferrer" href="%s">the documentation</a>.
 runs.no_runs = The workflow has no runs yet.
 runs.empty_commit_message = (empty commit message)