Use an LLM for diplomatic messages

**What do you want to see?**
This is just a crazy idea but what if the diplomatic messages used by AI players (and the default messages when human players choose to, say, form a treaty) were generated by a large language model (LLM)?

**How would it help players?**
More diverse messages

**Alternatives**
???

**Screenshots and mockups**
N/A

**Things to consider**
What if the LLM starts swearing at players and telling them of the glory of the Chinese Communist Party 😂

**Related issues**
#7