Replace connexion[swagger-ui] dependency with dedicated swagger-ui container

[lewismc]

By default we provide a swagger-iu web application packaged with connexion via requirements.txt.

Recently this some drawbacks have materialized, namely

1. the administrator is not able to toggle this on or off... they must deploy it
2. the dependency on swagger-ui is causing some renovate dependency upgrades to fail i.e. chore(deps): update dependency werkzeug to v2.3.7 - autoclosed #243 and chore(deps): update dependency flask to v2.3.3 #242 this has to do with more complex upstream transitive dependency management.

I think we should run a dedicated swagger-ui container which can be toggled on and off by passing a command line argument override to docker-compose or similar.