New doc - MEAI evaluation quickstart

[alexwolfmsft]

Describe the issue or suggestion

Create a new doc that explains how to get started using MEAI for evaluations. Evaluations refer to the process of assessing the quality and accuracy of responses generated by AI models, such as SLMs or LLMs. Cover the following topics:

• What are the MEAI evaluations libraries?
• How to evaluate your AI prompts using testing scenarios
• How to view and read the assessment results