This PR adds a `Preview` section and a `Open in StackBlitz` button to various examples. I have tested all examples and omitted the ones that require third party API keys, or didn't work. Some examples don't work locally either.
Here's an example:
![image](https://user-images.githubusercontent.com/12571019/121027783-88971280-c7a7-11eb-851a-0ad30cf74b42.png)
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [x] Examples updated
- [ ] Telemetry added. In case of a feature if it's used or not.
## Documentation / Examples
- [x] Make sure the linting passes
Closes [7882](https://github.com/vercel/next.js/issues/7882).
Created as requested by @timneutkens
I'm unsure if that's exactly what you wanted, so let me know what you want me to change and I'll do it asap.