Improvements in Mobile Steppers examples

[Klynger]

Adding better demos to two examples of Mobile Steppers. I decided add content to only two and let the third without it because I thought that would be nice to have one example with only the component.
Fixes #11155

[mbrookes]

Sorry to be a PITA, but for the "Mobile Stepper - Dots" example, I'm not seeing a "series of logical steps". Paginating a list like this seems to go against the spec.

For the "Mobile Stepper - Text" example (which is a carousel by any other name), if we're going to stick with photos as the "steps", the juxtaposition of "here's a beautiful landscape" to "here's the machine we used to destroy it" is a bit jarring! 🌴🚜

[Klynger]

Haha, didn't thought about the images that I was using. So, to correct this, in the "Mobile Stepper - Text" example I'm thinking about make some kinda a tutorial using the text as label and an image that illustrate that step (e.g. how to contribute to material-ui, fork the repo, etc..). And the dots example could be a form with several steps and maybe use the SwipeableViews component. Do you like my ideas?

[mbrookes]

@Klynger Sounds like a plan 👍

[oliviertassinari]

I agree with @mbrookes. The SwipeableViews integration is an advanced demo. I think that it would be better to keep the other demo as simple as possible (untouched) so people can copy&paste it in their code. While the "carousel mode" sounds like a "diverted" use case of the Stepper. I'm fine with adding a new advanced integration demo into the docs.