Add a way to build docker images using custom Dockerfile

[dombrovsky]

🚀 Feature Description

As a developer, I'd like to use custom Dockerfile for building images for Aspire project resources.

🧰 Possible Solution

• Add optional parameter to build and generate commands, that would instruct to use Dockerfile specified in DockerfileFile msbuild property in csproj to build docker image, instead of dotnet publish -t:PublishContainer. If csproj doesn't have DockerfileFile property set, but Dockerfile file exist in project directory, use it. Otherwise fallback to dotnet publish way for this project resource.
• Add optional parameter to build and generate commands to provide docker build arguments.

Considerations

Would be nice if custom Dockerfiles were supported by dotnet sdk. Depending on the final design for dotnet/sdk-container-builds#125, the solution for supporting custom Dockerfiles in Aspire8 may differ.