gha: nydus: Add a no-op GHA for nydus

This newly added GHA does nothing, is not even triggered, and it's just
a placeholder that we'll grow in the next commits / PRs, so we can
actually start running the nydus tests as part of our CI.

Fixes: #6543

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

.github/workflows/run-nydus-tests.yaml

@@ -0,0 +1,42 @@
+name: CI | Run nydus tests
+on:
+  workflow_call:
+    inputs:
+      tarball-suffix:
+        required: false
+        type: string
+      commit-hash:
+        required: false
+        type: string
+
+jobs:
+  run-nydus:
+    strategy:
+      fail-fast: true
+      matrix:
+        containerd_version: ['lts', 'active']
+        vmm: ['clh', 'qemu', 'dragonball']
+    runs-on: garm-ubuntu-2204
+    env:
+      CONTAINERD_VERSION: ${{ matrix.containerd_version }}
+      GOPATH: ${{ github.workspace }}
+      KATA_HYPERVISOR: ${{ matrix.vmm }}
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          ref: ${{ inputs.commit-hash }}
+
+      - name: Install dependencies
+        run: bash tests/integration/nydus/gha-run.sh install-dependencies
+
+      - name: get-kata-tarball
+        uses: actions/download-artifact@v3
+        with:
+          name: kata-static-tarball-amd64${{ inputs.tarball-suffix }}
+          path: kata-artifacts
+
+      - name: Install kata
+        run: bash tests/integration/nydus/gha-run.sh install-kata kata-artifacts
+
+      - name: Run nydus tests
+        run: bash tests/integration/nydus/gha-run.sh run