test legacy virtv2v migration with CI

[cloudguruab]

Summary

• Change connection URI from esx:// to vpx:// for vCenter
• URL-encode @ symbol in vCenter usernames
• Update virt_v2v.yml to use proper variables instead of hardcoded values
• Update unit tests to reflect new URI format

Fixes virt-v2v authentication with vCenter users containing @ symbols.
Enables customers to reproduce virt-v2v bugs using the legacy workflow.

[cloudguruab]

Testing with 17.1

[matbu]

LGTM overall, but I think we need to fix the find command:
https://github.com/os-migrate/vmware-migration-kit/blob/main/roles/import_workloads/tasks/virt_v2v.yml#L5

When I commit into your branch, I commited the fix for this step. If you can add it too, so we have a fully working v2v way.

[matbu]

This command should work:
set -o pipefail
find / -path /usr/share/doc -prune -o -name vmware-vix-disklib -print 2>/dev/null | xargs -r dirname | sort -u

[cloudguruab]

Will fix ansible lint checks after successful CI run 👍🏼