Add Open WebUI support for Ollama integration

[aaronpowell]

Related to an existing integration?

Yes

Existing integration

Hosting.Ollama

Overview

Open WebUI is a popular tool for interacting with Ollama, so we should have the ability to add it to the resource.

Usage example

builder.AddOllama("ollama")
.AddModel("llama3")
.WithOpenWebUI();

Breaking change?

None

Alternatives

No response

Additional context

Code can be lifted from https://github.com/dotnet/aspire/pull/4707/files#diff-7186a37a3f85cc4a242516c95f47fe2b45d942b9a1ac925b44773c90e5272c8aR132-R156

Help us help you

None