treewide foris: Makefile polishing

• Fix indentation
• Fix variable PKG_LICENSE_FILES
• Correct SPDX License Identifier
• Remove PKG_UNPACK
• Dont reuse PKG_NAME (more details: https://github.com/openwrt/packages/pull/4119)

Relicense it to GPL-3.0-or-later.

lang/python-ubus/Makefile

@@ -17,6 +17,7 @@ PKG_SOURCE_URL:=https://gitlab.labs.nic.cz/turris/python-ubus.git
 PKG_SOURCE_VERSION:=v$(PKG_VERSION)
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_SOURCE_VERSION).tar.gz
+
 PKG_BUILD_DIR:=$(BUILD_DIR)/$(BUILD_VARIANT)-$(PKG_NAME)-$(PKG_VERSION)
 
 include $(INCLUDE_DIR)/package.mk