Add a CTA button element for authors to add it in their posts without coding it

I want to be able to select simply a button element for users to send to a petition, donation download, SoMe event or any CTA directly from the post so that the CTA is more visible than a simple link and more direct than a Take action boxout that leads to a Take action page and not directly to the wanted page.

Jira ticket: PLANET-3351