Produce Ubuntu 24.04 images (Noble Numbat)

[richlander]

The next Ubuntu LTS is practically on our doorstep.

We should do the following:

• Do nothing for .NET 6/7
• Add Noble to .NET 8
• Ship only Noble (for Ubuntu) for .NET 9

[lbussell]

[Triage] We discussed if 9.0-preview.3 images should include Noble in the main branch before Noble's release. Since 9.0 is already a preview, it should be acceptable to ship Noble in the main branch as a preview for what we will actually ship. We don't want to maintain Jammy support for 9.0 since it's not in our plans to ship it.

[richlander]

Sounds great!

I might do a blog post about Noble in April, and this would be perfect context to include.