Strategized with @balazsorban44 to open one larger PR, with changes to individual examples as separate commits.
For each example, I researched how multiple realworld codebases use the featured technology with TypeScript, to thoughtfully convert them by hand - nothing automated whatsoever.
## Documentation / Examples
- [X] Make sure the linting passes by running `pnpm lint`
- [X] The "examples guidelines" are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)
* Examples: clarify language around Yarn create & npx
* add missing READMEs and create-next-app usage
* suggest people tag jthegedus in firebase related issues
* add yarn alt instructions
* cerebraljs example readme & fixes
* remove global npm install of create-next-app
* add npx to create-next-app command in examples
* add bash to shell snippets
* add yarn create to next-app command in examples
* fix READMEs named with lowercase
* change READMEs to use UPPERCASE
Got this fix from issue #2302. Libraries like `font-awesome` are pretty common. Indicating how to get them to work should be indicated in the `README.md` (if not added to the example)
* with-global-stylesheet without relative paths and with node_modules
* a parenthetical remark about material-components-web not being part of the example