Add support for translation endpoint

[stuartleeks]

See https://learn.microsoft.com/en-us/azure/ai-services/openai/reference#translations

• [ ] add generator for translations and include in default generators
• [ ] validate translation endpoint with record/replay
• [ ] determine how rate-limiting is applied and add to the simulator rate-limiting
• [ ] add tests
• [ ] add load test

(from https://github.com/stuartleeks/aoai-simulated-api/issues/47)

[wtulloch]

@stuartleeks I will try this one