aspire: Support Azure Functions Prototype

[ellismg]

The Aspire team has started to prototype Azure Functions support and this PR is the start of the support in azd for this deployment target under Aspire.

In the current prototype, Aspire models this as a new function.v0 resource type, which azd has special knowledge of. We need to do two special things with this resource type:

1. When generating IaC for the project, we need to generate IaC that allows us to use the Functions on ACA feature (where we can create a Microsoft.Web/sites resource with correct configuration to run a functions app on an existing container app environment)

2. Since function projects do not support using dotnet publish to produce a container image (there is work in flight to support this), we require a Dockerfile at the root of the project, which we docker build.

In the next phase of the prototype, we will replace function.v0 with project.v0, so the function.v0 manifest type will not live forever, but until, dotnet run and dotnet publish works as expected for Azure Functions projects, we'll continue to model this as its own type in the manifest.

Note that there are still a lot of rough edges here... The initial azd up works if you ensure your function app name in the app host is unique across all of azure but future updates seem to hang. Also, none of the corresponding aspire support is in tree yet, so this is not something that anyone can just pick up and use right now, but I want to get the work out from behind our -pr repository and rebased on top of the latest main as we are starting to pick up steam on this work.