🚀 Documentation: Add Komga to examples

[lnlyssg]

Documentation Request

I'd love to submit a PR for this myself but having read the guide it's all a bit beyond me....

This is a guide for https://komga.org

Pocket ID Setup

1. In Pocket ID, create a new OIDC client named Komga.
2. (Optional) Set a logo for the OIDC client.
3. Set the callback URL to: https://<komga host>/login/oauth2/code/pocket-id, or leave blank to autofill on first login.
4. Copy the Client ID, Client Secret, and Issuer URL for the next steps.

Komga set-up

Create an application.yml file in your Komga directory and populate it like the below:

spring:
  security:
    oauth2:
      client:
        registration:
          pocket-id:
            provider: pocket-id
            client-name: pocket-id
            client-id: <client ID>
            client-secret: <client secret>
            scope: openid,email,profile
            authorization-grant-type: authorization_code
            redirect-uri: https://<komga host>/login/oauth2/code/pocket-id
        provider:
          pocket-id:
            user-name-attribute: preferred_username
            issuer-uri: https://<Issuer URL>

Restart Komga and test the Oauth login.