vnc: Add system-level integration

 * RC script, included automatically when added to PRODUCT_PACKAGES
 * SELinux policy, add to BOARD_SEPOLICY_DIRS
 * Disable spammy debug output
diff --git a/sepolicy/file_contexts b/sepolicy/file_contexts
new file mode 100644
index 0000000..9c73aa4
--- /dev/null
+++ b/sepolicy/file_contexts
@@ -0,0 +1 @@
+/system/bin/vncflinger   u:object_r:vncflinger_exec:s0