[EmptySpace] - Adding actionList props for primary and secondary actions to make Buttons work as Popovers

[aeperea]

WHY are these changes introduced?

App discovery in admin proposes to add dropdown options to the primary button for the EmptySpace component to add more functionality to the component. In order to allow this we propose adding a set of props actionList and secondaryActionList (the latter to add the same functionality to the secondaryAction button) of the type ActionListItemDescriptor[]. When the prop is present the button works as a Popover and which displays the actions under each of the primary and secondary buttons.

WHAT is this pull request doing?

Adding new props actionList and secondaryActionList. Defines a function that builds the markup depends on how the props are presented. Adding a new story to the storyboard and tests that verify that the right elements are being displayed with the provided props.

How to 🎩

🖥 Local development instructions
🗒 General tophatting guidelines
📄 Changelog guidelines

🎩 checklist

• Tested a snapshot
• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility
• Updated the component's README.md with documentation changes
• Tophatted documentation changes in the style guide

[aeperea]

Close due to Polaris UX not approving the new design