Kong Identity: OAuth migration

## Jobs to be done (optional)
Users need to know how they can programmatically migrate from Kong EE OAuth to Kong Identity with OAuth.

## Definition of done
- Create a reference page (difficult to write prereqs since this is a migration) that contains both the scripts and the steps to do this. Steps:
1. Fetch all consumers (with pagination) `GET /consumers`
2. Fetch OAuth2 apps for each consumer `GET /consumers/$CONSUMER_ID/oauth2`
3. Copy the client ID and secret
4. Upsert each client into Konnect auth serverPUT /v1/auth-servers/$AUTH_SERVER_ID/clients/$CLIENT_ID

Limitations/diverging from the happy path notes:
- cutover: outline different options
- more likely to switch over at the routing level slowly not one big cutover
- frame for risk-adverse, show where the customers can jump off if they aren't risk adverse
- map client to consumer as most likely/recommended, but not the only option (can use custom ID)
- decK might need transformations

Scripts:
[import_kong_oauth_clients_to_konnect.py](https://github.com/user-attachments/files/27066965/import_kong_oauth_clients_to_konnect.py)
[export_kong_oauth_clients.py](https://github.com/user-attachments/files/27066974/export_kong_oauth_clients.py)

For an outline, I'm thinking:
* Steps as API request examples, explaining why we are doing each and what it's doing
* Scripts as collapsed inline code blocks in case they want a programatic way to do it
* Explanation of limitations and ways to diverge from the happy path from https://docs.google.com/document/d/16z2nl9bgBii11UQUr6m0AYPreyjvVR5KmZBSkWb9pAA/edit?tab=t.eetvsrdxvyj4#heading=h.tjond3hwz928

## Information
DRP: Andrew J.

## Due date (optional)

## Size
L

Start by reading import_kong_oauth_clients_to_konnect.py and export_kong_oauth_clients.py, then compare their requests with the migration steps in the issue. Use the linked Google document for the limitation and cutover guidance. Done means a reference page includes API examples, both scripts as inline code, and documented migration options and divergences from the happy path.

Written by the indexing model from the issue text.