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/flt_http_comp.c b/src/flt_http_comp.c
index 30b5aad..6641249 100644
--- a/src/flt_http_comp.c
+++ b/src/flt_http_comp.c
@@ -11,13 +11,13 @@
  */
 
 #include <haproxy/api.h>
+#include <haproxy/cfgparse.h>
 #include <haproxy/compression.h>
 #include <haproxy/dynbuf.h>
 #include <haproxy/filters.h>
 #include <haproxy/http.h>
 #include <haproxy/http_ana-t.h>
 #include <haproxy/http_htx.h>
-#include <common/cfgparse.h>
 #include <haproxy/htx.h>
 #include <haproxy/list.h>
 #include <haproxy/proxy-t.h>