Drop testing/rolling releases

[dann1]

Dropped apps

• debian12
• alt sisyphus

Update documentation to notify the dropped appliances when the context release is made.

• [x] https://github.com/OpenNebula/addon-context-linux#tested-platforms
• [x] https://docs.opennebula.io/6.6/intro_release_notes/release_notes/platform_notes.html#linux-contextualization-packages

Remove old marketplace appliances 6.6.0 versions of the dropped releases @rsmontero ? They could cause confusion due not having the new features/fixes.

Note

Dropped means that there won't be marketplace images for them nor tests in our internal testing pipelines. The context packages can still be installed on them.