REORG: include: move cfgparse.h to haproxy/cfgparse.h

There's no point splitting the file in two since only cfgparse uses the
types defined there. A few call places were updated and cleaned up. All
of them were in C files which register keywords.

There is nothing left in common/ now so this directory must not be used
anymore.
diff --git a/src/hlua.c b/src/hlua.c
index ef41e7d..fd5ba06 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -26,7 +26,7 @@
 #include <import/ebpttree.h>
 
 #include <haproxy/arg.h>
-#include <common/cfgparse.h>
+#include <haproxy/cfgparse.h>
 #include <haproxy/channel.h>
 #include <haproxy/cli.h>
 #include <haproxy/connection.h>