docs: use new nuxi module add command in installation (#724)

Author: danielroe

README.md

@@ -15,7 +15,7 @@
 ## Quick Start
 
 ```sh
-npm i -D @sidebase/nuxt-auth
+npx nuxi@latest module add sidebase-auth
 ```
 
 Then visit the [Quick Start documentation](https://sidebase.io/nuxt-auth/getting-started/quick-start) to setup the module for <= v0.5 - the current stable version.

docs/content/1.getting-started/2.installation.md

@@ -4,18 +4,10 @@ description: "How to install nuxt-auth."
 
 # Installation
 
-You can install `nuxt-auth` via `npm`, `yarn` or `pnpm`:
-::code-group
-```bash [npm]
-npm i -D @sidebase/nuxt-auth
-```
-```bash [yarn]
-yarn add --dev @sidebase/nuxt-auth
+You can install `nuxt-auth` using `nuxi`:
+```bash
+npx nuxi@latest module add sidebase-auth
 ```
-```bash [pnpm]
-pnpm i -D @sidebase/nuxt-auth
-```
-::
 
 ## Specifics: `authjs`-Provider