Add GitHub workflow and luacheck (#545)

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

.luacheckrc

@@ -0,0 +1,48 @@
+unused_args = false
+allow_defined_top = true
+max_line_length = 999
+
+globals = {
+    "technic", "minetest",
+    "srcstack",
+}
+
+read_globals = {
+    string = {fields = {"split", "trim"}},
+    table = {fields = {"copy", "getn"}},
+
+    "intllib", "VoxelArea",
+    "default", "stairsplus",
+
+    "PseudoRandom", "ItemStack",
+    "mg", "tubelib", "vector",
+
+    "moretrees", "bucket",
+    "unified_inventory", "digilines",
+
+    "pipeworks", "screwdriver",
+    "VoxelManip", "unifieddyes",
+
+    "Settings", "mesecon",
+    "digiline_remote",
+
+    "protector", "isprotect",
+    "homedecor_expect_infinite_stacks",
+}
+
+files["concrete/init.lua"].ignore = { "steel_ingot" }
+files["technic/machines/MV/tool_workshop.lua"].ignore = { "pos" }
+files["technic/machines/other/frames.lua"].ignore = { "item_texture", "item_type", "adj", "connected", "" }
+files["technic/machines/register/battery_box.lua"].ignore = { "pos", "tube_upgrade" }
+files["technic/machines/register/cables.lua"].ignore = { "name", "from_below", "p" }
+files["technic/machines/register/common.lua"].ignore = { "result" }
+
+files["technic/machines/register/generator.lua"].ignore = { "node" }
+files["technic/machines/switching_station.lua"].ignore = { "pos1", "tier", "poshash" }
+files["technic/radiation.lua"].ignore = { "LAVA_VISC" }
+files["technic/tools/chainsaw.lua"].ignore = { "pos" }
+files["technic/tools/mining_drill.lua"].ignore = { "mode" }
+files["technic_chests/register.lua"].ignore = { "fs_helpers", "name", "locked_after_place" }
+
+files["technic_cnc/cnc.lua"].ignore = { "multiplier" }
+files["wrench/init.lua"].ignore = { "name", "stack" }