Add luacheck CI and drop node_ownership remnants (#44)

`node_ownership` is long dead, and pollutes the global namespace. Support dropped after ~7 years.

Co-authored-by: BuckarooBanzay <BuckarooBanzay@users.noreply.github.com>

.github/workflows/luacheck.yml

@@ -0,0 +1,17 @@
+name: luacheck
+
+on: [push, pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: apt
+      run: sudo apt-get install -y luarocks
+    - name: luacheck install
+      run: luarocks install --local luacheck
+    - name: luacheck run
+      run: $HOME/.luarocks/bin/luacheck ./