Enhancement request: MDTabs 2.0.1 - added 2 examples

[RobertFlatt]

Description of the Feature

I wish to do lazy loading of MDTabsPrimary tabs and tab content with KivyMD 2.X , because the data displayed comes from some server. Of course I assume I must statically define at least one tab and its contents.

I would like

1. a method to append a new tab (and it's contents) at any time step.
2. a method to replace the content of any existing tab at any time step.

I was able implement lazy loading of tabs with KivyMD 1.X

Thanks for your time, I think version 2 is great.