Allow setting the color for controls in the browser toolbar

[JanMisker]

This PR implements setting a color for the controls in the browser overlay, as mentioned in #911 .
I only made changes for iOS, not sure if something is needed for Android.

So now next to the toolbarColor you can also set a controlsColor in the params for Browser.open, e.g.

Browser.open({
   url: "https://capacitorjs.com",
   toolbarColor: "#ff0000",
   controlsColor: "#00ff00"
});

[WouterWidgets]

Would love to see this one merged and published 🙏

[codemis]

I would love to see this merged in and available. 🤓 👍

[eric-horodyski]

Thanks for opening this PR 🙏

As part of our backlog maintenance effort, we’re reviewing older pull requests for compatibility with the current branch structure and latest releases.

Details: https://ionic.io/blog/keeping-capacitors-backlog-healthy

This PR will need to be rebased against the latest main branch and updated to resolve merge conflicts.

If we don’t see updates within 7 days, we’ll close it to keep the queue focused — but it can always be resubmitted once updated.