REORG: include: move base64.h, errors.h and hash.h from common to to haproxy/

These ones do not depend on any other file. One used to include
haproxy/api.h but that was solely for stddef.h.
diff --git a/include/proto/stick_table.h b/include/proto/stick_table.h
index 2243d3d..986c775 100644
--- a/include/proto/stick_table.h
+++ b/include/proto/stick_table.h
@@ -23,7 +23,7 @@
 #ifndef _PROTO_STICK_TABLE_H
 #define _PROTO_STICK_TABLE_H
 
-#include <common/errors.h>
+#include <haproxy/errors.h>
 #include <common/ticks.h>
 #include <common/time.h>
 #include <types/stick_table.h>