cm: Rework boot animation generation

Keep the largest bootanimation extracted
and resize it at build-time.

Change-Id: Iee32f18440ff955d13ed85b273e97cbd540721fc
diff --git a/bootanimation/desc.txt b/bootanimation/desc.txt
new file mode 100644
index 0000000..4aecc8e
--- /dev/null
+++ b/bootanimation/desc.txt
@@ -0,0 +1,3 @@
+c 1 0 part0
+c 0 0 part1
+c 1 0 part2