Switch to .NET 8

[melotic]

Switching to .NET 8 is slated to bring performance improvements, and is the latest LTS version of .NET.

There are so some much needed changes to System.Text.Json to make #231 easier

AB#2102423

[melotic]

.NET 8.0.100-rc.1 was just released yesterday, and is a go-live release: https://dotnet.microsoft.com/en-us/download/dotnet/8.0

[cobya]

.NET release 8.0.0 was released on November 14th, 2023. See 8.0.0 release notes for more details.

[cobya]

There is an ask to support .NET 8 for ARM64 for OSX in the sbom-tool via an internal issue.