Add GitHub workflow and luacheck (#545)

Add badge to README
Fix luacheck warnings
Remove node_ownership globals (and support)

.github/workflows/check-release.yml

@@ -0,0 +1,11 @@
+on: [push, pull_request]
+name: Check & Release
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+      - name: lint
+        uses: Roang-zero1/factorio-mod-luacheck@master
+        with:
+          luacheckrc_url: https://raw.githubusercontent.com/minetest-mods/technic/master/.luacheckrc