lua: move Lua packages under lang/lua sub-folder

There are roughly 50 Lua packages.
It's about time we consider a proposal for moving all of them
under a lang/lua sub-folder.

Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>

lang/lua/lua-libmodbus/Makefile

@@ -0,0 +1,40 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=lua-libmodbus
+PKG_VERSION:=0.7
+PKG_RELEASE:=1
+
+PKG_SOURCE:=lua-libmodbus-$(PKG_VERSION).tar.gz
+PKG_SOURCE_SUBDIR:=lua-libmodbus-$(PKG_VERSION)
+PKG_SOURCE_URL:=https://codeload.github.com/etactica/lua-libmodbus/tar.gz/v$(PKG_VERSION)?
+PKG_HASH:=70369f4c4e36421095bf00dcee36c633b4284eaa79bcfdfd230bfefb27acefda
+PKG_SOURCE_VERSION:=v$(PKG_VERSION)
+
+PKG_MAINTAINER:=Karl Palsson <karlp@etactica.com>
+PKG_LICENSE:=MIT
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/lua-libmodbus
+  SUBMENU:=Lua
+  SECTION:=lang
+  CATEGORY:=Languages
+  TITLE:=lua-libmodbus
+  URL:=https://github.com/etactica/lua-libmodbus
+  DEPENDS:=+liblua +libmodbus
+endef
+
+define Package/lua-libmodbus/description
+	lua-libmodbus is a binding to libmodbus,
+	see also http://www.libmodbus.org
+endef
+
+define Build/Configure
+endef
+
+define Package/lua-libmodbus/install
+	$(INSTALL_DIR) $(1)/usr/lib/lua
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/libmodbus.so $(1)/usr/lib/lua
+endef
+
+$(eval $(call BuildPackage,lua-libmodbus))