For Aspire 8.0 GA, some branding and version updates are needed in various docs to clearly indicate that Aspire is not in preview anymore

[balachir]

Describe the issue or suggestion

Issue description In the following docs, some branding updates are needed for GA.

In various docs like Build your first .NET Aspire app and Add Aspire to existing app

• [ ] In Prerequisites section, remove 'preview' label from 'Visual Studio 2022' and change it to 'version 17.10 or higher'

In the doc Build your first .NET Aspire app

• [ ] In the .NET Aspire app host project and .NET Aspire service defaults project sections, change PackageReference versions in the code to 8.0.0

In the doc Setup and tooling

• [ ] In the '.NET Aspire dashboard' section, change screenshot to show Aspire version as 8.0.0

• [ ] In the Add hosting packages section, remove the part about asking the user to check 'Include prerelease' in NuGet package manager dialog. Or alternatively, we should call out that this is needed only for Aspire preview releases.

---

Associated WorkItem - 255385