Add .NET Aspire support to AI Chat Web App template

[jmatthiesen]

In Preview 1 of the AI Chat Web App template, we ship a single project Blazor Web app. Now, we want to iterate on this and create a .NET Aspire-specific template that demonstrates the best starting point for AI + .NET Aspire.

Initial Proposal:

• Create a new template named "AI Chat .NET Aspire App": We still want a self-contained web app project for non-Aspire scenarios, and to setup the Aspire solution correctly it's not a simple "Add Aspire Orchestration" checkbox for the existing project.
• The core functionality of the .NET Aspire template is the same as the AI Chat Web App template: Support for GitHub Models, OpenAI, Azure OpenAI, Ollama, Azure AI Search. With the same data ingestion handling & UI.
• Leverage .NET Aspire Integrations for each service, as well as Ollama.

Questions to answer:

• How do we demonstrate using a 3rd party vector store as a container?