Support personal data eraser feature

We can integrate with WordPress's personal data eraser feature.

Docs here: https://developer.wordpress.org/plugins/privacy/adding-the-personal-data-eraser-to-your-plugin/

This would be implemented via the following two methods:

- Send current endpoint ID with request
- Delete all records in Elasticsearch and if possible the S3 data lake
- If user is logged in delete data where the User ID matches the `endpoint.User.UserId` value

There is a very difficult barrier to making this work right now in that the requests for data removal and export don't happen via a form on the website. We would need this to be able to pass the endpoint ID along.

An alternative would be to display the current endpoint ID to users on the privacy policy page perhaps using a special gutenberg block.

This issue needs more research into the technical feasibility. There may be a point during the data removal approval request where we can extract the endpoint ID if the user is directed to the website.

Blocked by #18