IMPROVEMENT: Add functions to go forward

[ludonoel1]

Describe the bug
It should be awesome to manipulate steps next - previous with functions.

To Reproduce
Steps to reproduce the behavior:
Go to demo

• add pointer-events: none on joyride-container.
• click on step1 and try go to forward
• but today there is nothing to go forward with a click (outside prev -next) or a var or method

Expected behavior
The possibility to send an event or to call this.joyride.next() to go forward or previous.
My goal is to handle the click on a targeted button (step 1) and go to step 2
Screenshots
Details (please complete the following information):

• Browser [e.g. chrome, safari] + version
• List of the dependencies with their version (Angular, rxjs, ngx-joyride,...)

Additional context
Add any other context about the problem here.