Set up a React example

[mesqueeb]

steps to open the vue example

1. pnpm i
2. npm run dev:vue3-firestore

we need to add a new folder called dev-react-firestore which looks and works the same as dev:vue3-firestore

the magnetar instance is instantiated with PluginVue3 and PluginFirestore, but the react one can use PluginSimpleStore and PluginFirestore. The rest of the syntax can be the exact same.