repack: move sbin to /system ramdisk and update repacking

for android-10

This will support updating the ramdisk to a different
compression format and co-exist with magisk.

We are also cleaning up and removing non android-10
api makefile actions.

We are also moving twrp repacking to its own class. We
check the new ramdisk format and if it's different
we have magisk compress using the new ramdisk format.

Change-Id: I770030aae7797e75817178b2f0fccd9f39dc23af

gui/terminal.cpp

@@ -116,7 +116,7 @@ public:
 		// (Mandatory for programs like the shell to make them manage correctly their outputs)
 		ioctl(0, TIOCSCTTY, 1);
 
-		execl("/sbin/sh", "sh", NULL);
+		execl("/system/bin/sh", "sh", NULL);
 		_exit(127);
 	}