feat(ubuntu): Allocate all LVM available space to root volume on Ubuntu boxes

[brandon-welsch]

Description

Configure Ubuntu autoinstall LVM layouts with sizing-policy: all so the root logical volume uses all available volume-group space. This prevents the default scaled policy from leaving roughly half of a 64 GiB disk unallocated on Ubuntu 22.04, 24.04 and 26.04 boxes.

Related Issue

Fix #1693

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist

• I have read the CONTRIBUTING document.
• I have run the pre-merge tests locally and they pass.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• If Gemfile.lock has changed, I have used --conservative to do it and included the full output in the Description above.
• All new and existing tests passed.
• All commits have been signed-off for the Developer Certificate of Origin.

Additional checks

• YAML parsing passed
• cloud-init schema passed
• Packer validate passed for Ubuntu 22, 24 and 26