Vlab show tech

[pau-hedgehog]

Gathers outputs from the different VMs/SWs in the VLAB to allow forensic analysis when a vlab up ends/fails

Fixes #335

[Frostman]

@pau-hedgehog looks like it's not collecting data when running the upgrade scenario

[pau-hedgehog]

@pau-hedgehog looks like it's not collecting data when running the upgrade scenario

This is because the old version still does not have show-tech helper support:

      - name: Initial VLAB with old version
        env:
          HHFAB_REG_REPO: 127.0.0.1:30000
        run: |
          mkdir old
          curl -fsSL https://i.hhdev.io/hhfab | USE_SUDO=false INSTALL_DIR=./old VERSION="${{ matrix.fromversion }}" bash

          old/hhfab init -v --dev -m ${{ matrix.fabricmode }} --include-onie=true
          old/hhfab vlab gen -v
          old/hhfab vlab up -v --ready setup-vpcs --ready test-connectivity --ready exit ${{ matrix.fromflags }}