Change documentation to a better format (#25)

Added new documentation style, added Authentik & Authelia examples. THank you Hendrik & Ivan!

---------

Co-authored-by: Hendrik Sievers <89412959+hendrik1120@users.noreply.github.com>
Co-authored-by: Ivan Vasquez <ivanvasquezp@outlook.com>

docs/provider-configurations/authentik.md

@@ -0,0 +1,40 @@
+# Authentik
+
+## Public client configuration
+Under construction.
+
+## Confidential client configuration
+
+1. From the admin interface, go to `Applications > Providers` and click on `Create`
+2. Select `OAuth2/OpenID Provider` and click `Next`
+3. Fill the following details:
+    - Name: `Home Assistant Provider`
+    - Authorization flow: `default-provider-authorization-explicit-consent`
+    - Client type: `Confidential`
+    - Client ID: `homeassistant`
+    - Client Secret: **Copy this value**
+    - Redirect URIs/Origins: Click on `Add entry` (You can use either DNS, Internal/External IP or localhost)
+        - Strict: https://hass.example.com/auth/oidc/callback
+4. Click `Finish` to save the provider configuration
+5. Open the created Provider 
+6. On the Assigned to application section click on `Create`:
+    - Name: `Home Assistant`
+    - Slug: `home-assistant`
+    - Provider: `Home Assistant Provider`
+    
+    Then save the configuration
+
+## Home Assistant configuration
+
+> [!IMPORTANT]  
+> For HTTPS configuration make sure to have a public valid SSL certificate (i.e. LetsEncrypt), if not, use HTTP instead (more insecure) or add your Authentik CA certificate to `network.tls_ca_path`.
+
+After installing this HACS addon, edit your `configuration.yaml` file and add:
+```yaml
+auth_oidc:
+  client_id: "homeassistant"
+  client_secret: "client_secret"
+  discovery_url: "https://auth.example.com/application/o/home-assistant/.well-known/openid-configuration"
+```
+
+Restart Home Assistant and go to https://hass.example.com/auth/oidc/welcome