Implement proper vm name passing

[avnik]

Description

Implement proper vm name passing

Checklist

• Summary of the proposed changes in the PR description
• More detailed description in the commit message(s)
• Commits are squashed into relevant entities - avoid a lot of minimal dev time commits in the PR
• Contribution guidelines followed
• Test procedure added to nixos/tests
• Author has run nix flake check --accept-flake-config and it passes
• All automatic Github Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing

nix flake check or run-vm-test admin.

givc-cli .... start --vm vmname appname should start in vmname VM