Apim aoai pattern

[ayuina]

This pull request includes changes to the apim-aoai-pattern project to improve load balancing, error handling, and code readability. The most important changes include adding new Bicep templates and policies, modifying existing ones, and adding new code snippets to the index.md file.

Changes to Bicep templates and policies:

• apim-aoai-pattern/template/apim.bicep: Added new resources for log analytics, application insights, and API management, and updated the API management resource to include a logger.
• apim-aoai-pattern/template/aoai-default-policy.xml: Added a new default policy for the API.
• apim-aoai-pattern/template/burst-old.bicep: Added resources for the completion and completionSub modules, and their corresponding backends.
• apim-aoai-pattern/template/burst.bicep: Added resources for the completion, completionSub, and completionBurstPool modules, and their corresponding backends. Also added a policy for operations.
• apim-aoai-pattern/template/facade.bicep: Added parameters for the name, aoaiOpsName, region, deployName, modelName, modelVersion, modelCapacity, and policy. Also added resources for the aoaiApi and operation modules, and their corresponding backends.

Changes to index.md:

• Added new code snippets to demonstrate how to use Azure API Management for load balancing and error handling. [1] [2] [3]
• Updated existing code snippets to improve readability. [1] [2] [3]