Update browser extension button style and order

Thanks @corneliusludmann for making this change!

However, I think this slightly degrades the user experience for GL and GH products since this will a) introduce a flickering button on page load across multiple pages and b) remove the primary button for repository cloning, opening an issue, and more.

I understand the intent of this change but this will break common navigation patterns used by GL and GH users, contributors, and maintainers as well as indirectly hurt overall UX for Gitpod. 😭

GL	GH

Question: What do you think of the proposal in https://github.com/gitpod-io/browser-extension/issues/24 to a) use a secondary button and b) move the action before the primary action? This would help a) avoid all the UX issues mentioned above, b) smoothly integrate with GL and GH without affecting their existing product UX, and c) will follow similar patterns used by other related extensions. [1]

/cc @svenefftinge

Originally posted by @gtsiolis in https://github.com/gitpod-io/browser-extension/pull/26#issuecomment-702792882

Start by locating the browser extension button implementation and review the proposal in issue 24 alongside the GitLab and GitHub examples linked here. Done means the extension action uses the proposed secondary styling and ordering without introducing page-load flicker or replacing the hosts' primary navigation actions.