Add a Doxyfile for update_engine codebase am: 8b113b21b8 am: 443bd55ac2 am: 7e5e496abd am: c0bafc6ec2

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1421968

Change-Id: I9e1c5cc0ee18a76bf83d189ae029d33b91a93818
diff --git a/Doxyfile b/Doxyfile
new file mode 100644
index 0000000..db31f86
--- /dev/null
+++ b/Doxyfile
@@ -0,0 +1,9 @@
+CLANG_DATABASE_PATH=../../
+HAVE_DOT=YES
+CALL_GRAPH=YES
+CALLER_GRAPH=YES
+GENERATE_HTML=YES
+GENERATE_LATEX=NO
+INPUT=.
+RECURSIVE=YES
+