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

A few includes had to be added, namely list-t.h in the type file and
types/proxy.h in the proto file. actions.h was including http-htx.h
but didn't need it so it was dropped.
diff --git a/src/cache.c b/src/cache.c
index 02083c0..0fa1c64 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -11,6 +11,7 @@
  */
 
 #include <haproxy/api.h>
+#include <haproxy/http_htx.h>
 #include <haproxy/shctx.h>
 #include <import/eb32tree.h>
 #include <import/sha1.h>
@@ -23,7 +24,6 @@
 #include <proto/channel.h>
 #include <proto/cli.h>
 #include <proto/proxy.h>
-#include <proto/http_htx.h>
 #include <proto/filters.h>
 #include <proto/http_rules.h>
 #include <proto/http_ana.h>