use security settings for the external api key to show the lock thing on the external-api/docs page.

we want the external api to be a bit more fun for users. This is a first step. Take a look in utils and postmark files for how the api key is used for the postmark endpoints which correctly shows the lock

Start by examining the utils and postmark files to see how the API key is used for endpoints that already show the lock. Then inspect the external-api/docs page and security settings integration; done means the external API documentation displays the lock consistently with the postmark endpoints.

Written by the indexing model from the issue text.