rework mod

* register armor using `armor:register_armor` (fixes #4)
* improve code readability
* make `technic_worldgen` optional
* add screenshot
* update readme and mod.conf
* remove integration test (unnecessary for a simple mod)
* remove other unnecessary files

.luacheckrc

@@ -1,32 +1,4 @@
-allow_defined_top = true
-unused_args = false
-
 globals = {
-	"wieldview",
 	"armor",
-	"inventory_plus"
-}
-
-read_globals = {
-	-- Stdlib
-	string = {fields = {"split"}},
-	table = {fields = {"copy", "getn"}},
-
-	-- Minetest
-	"vector", "ItemStack",
-	"dump", "VoxelArea",
-
-	-- deps
-	"default",
 	"minetest",
-	"unified_inventory",
-	"wardrobe",
-	"player_monoids",
-	"armor_monoid",
-	"sfinv",
-	"ARMOR_MATERIALS",
-	"ARMOR_FIRE_NODES",
-	"pova",
-	"skins",
-	"u_skins"
 }