Better appearance for context menu in pipeline view

[catto]

What happened:

Currently we can access some features from a context menu on pipeline view. These are three actions in it Go to build page, Go to build metrics and Start pipeline from here and they all look like just a link. Actually, the former two just navigate to other pages but the last one starts new build and it is hard for users to distinguish them.

What you expected to happen: Start pipeline from here looks different from others.