[docs] Add a new site to showcase (hifivework)

[lau-sam]

• I have followed (at least) the PR section of the contributing guide.

[mui-pr-bot]

No bundle size changes comparing 89cbce9...e7d5a02

Generated by 🚫 dangerJS against e7d5a02

[oliviertassinari]

No objection from my end, @mbrookes what do you think? Also, we will need the screenshot to respect the correct dimension (same as the others).

[lau-sam]

@oliviertassinari I'll resize the image and get you a new PR.

We're a start-up based in Montpellier, France. We have developed other products around MUI. I'll submit other products if you're interested. It's a great way to show what we can do with MUI.

There are our products :

• https://www.coderkaine.com/ (showcase website)
• https://demo.hifivework.com/#/ ( demo app, I am creating the demo system that allows people to log in to our application and see the design )
• http://demo.resilive.fr/#/ ( demo app, with demo user soon )
• http://www.resilive.fr/#/ ( showcase website for resilive product, not in https yet, It will be soon)

All the design of these projects are based on MUI with the dark/light mode implemented directly with the MUI theme.

I'm attaching screenshots of the 2 applications because for the moment I don't have a demo user system that allows you to navigate in the application. It will be done very soon.

[mbrookes]

LGTM!