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/src/ssl_ckch.c b/src/ssl_ckch.c
index 4a5f1c1..9011df9 100644
--- a/src/ssl_ckch.c
+++ b/src/ssl_ckch.c
@@ -21,8 +21,8 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include <common/base64.h>
-#include <common/errors.h>
+#include <haproxy/base64.h>
+#include <haproxy/errors.h>
 #include <common/standard.h>
 
 #include <import/ebsttree.h>