docs: add documentation of plugin

Author: vinayakkulkarni

docs/content/en/providers/office365.md

@@ -0,0 +1,35 @@
+---
+title: Office 365
+description: This provider is based on oauth2 scheme and supports all scheme options
+position: 38
+category: Providers
+---
+
+[Source Code](https://github.com/nuxt-community/auth-module/blob/dev/src/providers/o365/index.ts)
+
+## Usage
+
+```js
+auth: {
+  strategies: {
+      o365: {
+        clientId: process.env.AAD_CLIENT_ID,
+        clientSecret: process.env.AAD_CLIENT_SECRET,
+        tenantId: process.env.AAD_TENANT_ID,
+        grantType: 'authorization_code'
+      },
+  }
+}
+```
+
+Anywhere in your application logic:
+
+```js
+this.$auth.loginWith('o365')
+```
+
+💁 This provider is based on [oauth2 scheme](../schemes/oauth2.md) and supports all scheme options.
+
+## Obtaining configs
+
+You need to create an app registration from Azure Portal and make sure to set up everything for an OAuth app in the usual way. e.g. whitelist urls.