Move Google authentication to an external plugin

doc/google-authentication.markdown

@@ -1,64 +0,0 @@
-Google Authentication
-=====================
-
-Requirements
-------------
-
-OAuth Google API credentials (available in the Google Developer Console)
-
-How does this work?
--------------------
-
-- The Google authentication in Kanboard use the OAuth 2.0 protocol
-- Any user account in Kanboard can be linked to a Google Account
-- When a Kanboard user account is linked to Google, you can login with one click
-
-Procedure to link a Google Account
-----------------------------------
-
-1. Go to your user profile
-2. Click on **External accounts**
-3. Click on the link **Link my Google Account**
-4. You are redirected to the **Google Consent screen**
-5. Authorize Kanboard by clicking on the button **Accept**
-6. Your account is now linked
-
-Now, on the login page you can be authenticated in one click with the link **Login with my Google Account**.
-
-Your name and email are automatically updated from your Google Account.
-
-Installation instructions
--------------------------
-
-### Setting up OAuth 2.0 in Google Developer Console
-
-- Follow the [official Google documentation](https://developers.google.com/accounts/docs/OAuth2Login#appsetup) to create a new application
-- In Kanboard, you can get the **redirect url** in **Settings > Integrations > Google Authentication**
-
-### Setting up Kanboad
-
-Create a custom `config.php` file or copy the `config.default.php` file:
-
-```php
-<?php
-
-// Enable/disable Google authentication
-define('GOOGLE_AUTH', true); // Set this value to true
-
-// Google client id (Get this value from the Google developer console)
-define('GOOGLE_CLIENT_ID', 'YOUR_CLIENT_ID');
-
-// Google client secret key (Get this value from the Google developer console)
-define('GOOGLE_CLIENT_SECRET', 'YOUR_CLIENT_SECRET');
-```
-
-Notes
------
-
-Kanboard use these information from your Google profile:
-
-- Full name
-- Email address
-- Google unique id
-
-The Google unique id is used to link together the local user account and the Google account.

doc/index.markdown

@@ -118,7 +118,6 @@ Technical details
 - [LDAP authentication](ldap-authentication.markdown)
 - [LDAP group synchronization](ldap-group-sync.markdown)
 - [LDAP parameters](ldap-parameters.markdown)
-- [Google authentication](google-authentication.markdown)
 - [Github authentication](github-authentication.markdown)
 - [Gitlab authentication](gitlab-authentication.markdown)
 - [Reverse proxy authentication](reverse-proxy-authentication.markdown)