[MAJOR] udpated the stats page to clearly distinguish FEs and BEs

The stats page could not tell the difference between a FE and a BE.
It has been revamped to indicate all relevant information. The font
is also slightly smaller in order for all the info to fit into small
screens. The data output path has been greatly simplified to use
string chunks.
diff --git a/include/proto/proto_http.h b/include/proto/proto_http.h
index 82f68a1..45a42d7 100644
--- a/include/proto/proto_http.h
+++ b/include/proto/proto_http.h
@@ -46,6 +46,8 @@
 			int status, const struct chunk *msg);
 
 int produce_content(struct session *s);
+int produce_content_stats(struct session *s);
+int produce_content_stats_proxy(struct session *s, struct proxy *px);
 void debug_hdr(const char *dir, struct session *t, const char *start, const char *end);
 void get_srv_from_appsession(struct session *t, const char *begin, const char *end);
 void apply_filters_to_session(struct session *t, struct buffer *req, struct hdr_exp *exp);