[Feature Request] Add a tertiary button to the onboarding UI

[kryptonit1]

Is your feature request related to a problem? Please describe.
I would like to be able to have a button like the tertiary button in the onboarding UI. In some cases you might want to be able to open a URL where the user can read more information on a subject. Another use case would be to execute a Jamf policy to install a software during onboarding when the user presses a button.

Describe the solution you'd like
Please add a tertiary-like button in the onboarding UI which you can use for providing more information about a subject to the user via a web page (URL) and to launch Jamf policys. The onboarding UI should not be closed when this button is pressed though.

Describe alternatives you've considered
Using the HTML accessory view and just create a URL there, but it does not feel as "native" as a button in the onboarding UI.

Additional context
N/A