Add Support For Mistral on AWS Bedrock

[njedema]

• I have read and agree to the contributing guidelines.

Is your feature request related to a problem? Please describe.
AWS recently announced plans to support Mistral and Mixtral on Bedrock. I would like Griptape to support these models so that I can continue using Griptape.

Describe the solution you'd like
Implement a "BedrockMistralPromptModelDriver"

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

• Forking griptape and doing it myself
• Using langchain
• I can't open source this because I'm not allowed to contribute to open source per terms of my employment.

Additional context
Add any other context or screenshots about the feature request here.
https://aws.amazon.com/bedrock/mistral/