[CLEANUP] Move counters to dedicated structures

Move counters from "struct proxy" and "struct server"
to "struct pxcounters" and "struct svcounters".

This patch should make no functional change.
diff --git a/src/client.c b/src/client.c
index ec768d8..fe29b4c 100644
--- a/src/client.c
+++ b/src/client.c
@@ -255,7 +255,7 @@
 		s->data_source = DATA_SRC_NONE;
 
 		s->uniq_id = totalconn;
-		proxy_inc_fe_ctr(p);	/* note: cum_beconn will be increased once assigned */
+		proxy_inc_fe_ctr(l, p);	/* note: cum_beconn will be increased once assigned */
 
 		txn = &s->txn;
 		txn->flags = 0;
@@ -488,8 +488,8 @@
 		}
 
 		p->feconn++;  /* beconn will be increased later */
-		if (p->feconn > p->feconn_max)
-			p->feconn_max = p->feconn;
+		if (p->feconn > p->counters.feconn_max)
+			p->counters.feconn_max = p->feconn;
 
 		actconn++;
 		totalconn++;