Adding aspire to existing application - tutorial

[Meir017]

Where to start from?
How to do this gradually?

I would expect something like:

1. Introduce AppHost with 0 changes to existing services
2. Introduce ServiceDefaults
3. Replace client libraries with aspire integration libraries

[IEvangelist]

Hi @Meir017 - I'd love your feedback on this PR: #67

[Meir017]

@IEvangelist BTW, having a staging deployment for PRs would really simplify reviewing, the astro app has some special syntax and the screenshot by copilot are really long which reduces their quality so they are not that useful.