Analyzer to prevent mixing Sync with Async which causes Synchronous operations are disallowed error

### Description

1. Create an analyzer that will provide compile time validation and code suggestion to fix/prevent the issue.
2. Add this information to the migration guides (including highlighting the fact that ASP.NET Core behaviors apply when using the integration

See https://github.com/Azure/azure-functions-dotnet-worker/issues/2184

Start by reading the linked issue #2184 and the repository's migration guides to understand the reported synchronous-operation failure and the ASP.NET Core integration behavior. Define the analyzer's validation and code-suggestion scope, then update the migration guidance; done means both compile-time prevention and the requested documentation are covered.

Written by the indexing model from the issue text.