REORG: include: move sample.h to haproxy/sample{,-t}.h

This one is particularly tricky to move because everyone uses it
and it depends on a lot of other types. For example it cannot include
arg-t.h and must absolutely only rely on forward declarations to avoid
dependency loops between vars -> sample_data -> arg. In order to address
this one, it would be nice to split the sample_data part out of sample.h.
diff --git a/src/ssl_sample.c b/src/ssl_sample.c
index f27b2e6..509b0c5 100644
--- a/src/ssl_sample.c
+++ b/src/ssl_sample.c
@@ -24,16 +24,15 @@
 #include <haproxy/buf-t.h>
 #include <haproxy/obj_type.h>
 #include <haproxy/openssl-compat.h>
+#include <haproxy/sample.h>
 #include <haproxy/ssl_utils.h>
 #include <haproxy/tools.h>
 
-#include <types/sample.h>
 #include <types/ssl_sock.h>
 
 #include <proto/acl.h>
 #include <haproxy/arg.h>
 #include <proto/ssl_sock.h>
-#include <proto/sample.h>
 
 
 /***** Below are some sample fetching functions for ACL/patterns *****/