CLEANUP: include: tree-wide alphabetical sort of include files

This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
diff --git a/src/lb_chash.c b/src/lb_chash.c
index 1fb44f4..9f7ad5c 100644
--- a/src/lb_chash.c
+++ b/src/lb_chash.c
@@ -17,8 +17,8 @@
  */
 
 #include <import/eb32tree.h>
-#include <haproxy/backend.h>
 #include <haproxy/api.h>
+#include <haproxy/backend.h>
 #include <haproxy/queue.h>
 #include <haproxy/server-t.h>
 #include <haproxy/tools.h>