Add .NET 10 support

[justinyoo]

Summary

• add net10.0 to the library and test target frameworks while retaining .NET 8 and .NET 9 compatibility
• move the sample applications, container images, App Service runtime, and CI setup to .NET 10
• introduce central package management for the shared test dependencies
• remove the redundant ASP.NET Core Components package reference and refresh the README

Commit history

• c1ad7e6 Update to support .NET 10

Validation

• dotnet test Aliencube.Azure.Extensions.EasyAuth.sln --configuration Release (27 passed across .NET 8, .NET 9, and .NET 10)
• .NET 10 container image build succeeded
• Bicep compilation succeeded (with one pre-existing nullable-resource warning in fetch-container-image.bicep)