REORG: proto_htx: Move HTX analyzers & co to http_ana.{c,h} files

The old module proto_http does not exist anymore. All code dedicated to the HTTP
analysis is now grouped in the file proto_htx.c. So, to finish the polishing
after removing the legacy HTTP code, proto_htx.{c,h} files have been moved in
http_ana.{c,h} files.

In addition, all HTX analyzers and related functions prefixed with "htx_" have
been renamed to start with "http_" instead.
diff --git a/Makefile b/Makefile
index 950cee5..419d3ea 100644
--- a/Makefile
+++ b/Makefile
@@ -756,7 +756,7 @@
 endif
 endif
 
-OBJS = src/proto_http.o src/cfgparse-listen.o src/proto_htx.o src/stream.o    \
+OBJS = src/http_ana.o src/cfgparse-listen.o src/stream.o                      \
        src/mux_h2.o src/stats.o src/flt_spoe.o src/server.o src/checks.o      \
        src/haproxy.o src/cfgparse.o src/flt_http_comp.o src/http_fetch.o      \
        src/dns.o src/stick_table.o src/mux_h1.o src/peers.o src/standard.o    \