fix(vm): set disk serial by uid resource

[yaroslavborbat]

Description

Disk serials are now generated using the MD5 hash of the disk uid instead of the disk name itself. This prevents errors caused by recent QEMU changes enforcing a strict 36-character limit on serial numbers.

Why do we need it, and what problem does it solve?

What is the expected result?

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: vm  
type: fix  
summary: disk serials are now generated using the MD5 hash of the disk uid instead of the disk name itself; this prevents errors caused by recent QEMU changes enforcing a strict 36-character limit on serial numbers