Navigation bar apps (Reorder apps) implementation in Outlook for mobile (IOS) and OfficeJS

Question

We are looking for a way to add a non-contextual addin to our Outlook for mobile OfficeJs plugin. This is a screenshot of some possible places:

Notice that there is a Youtube app which is a 3rd party app.

Another possible way is to add a command like this:

Please let me know if the Navigation bar or the commands are extensible or now and how to do that in office js.

Thanks a lot.