Make hibernate timeouts configurable

Two *global* options added:
c2s_hibernate and receiver_hibernate.

Default if not specified is 90000, the previous hardcoded value.

src/ejabberd_c2s.erl

@@ -133,7 +133,7 @@
 %% session:
 -define(C2S_OPEN_TIMEOUT, 60000).
 
--define(C2S_HIBERNATE_TIMEOUT, 90000).
+-define(C2S_HIBERNATE_TIMEOUT, ejabberd_config:get_option(c2s_hibernate, fun(X) when is_integer(X); X == hibernate-> X end, 90000)).
 
 -define(STREAM_HEADER,
 	<<"<?xml version='1.0'?><stream:stream "

src/ejabberd_receiver.erl

@@ -56,7 +56,8 @@
          xml_stream_state :: fxml_stream:xml_stream_state(),
          timeout = infinity:: timeout()}).
 
--define(HIBERNATE_TIMEOUT, 90000).
+-define(HIBERNATE_TIMEOUT, ejabberd_config:get_option(receiver_hibernate, fun(X) when is_integer(X); X == hibernate-> X end, 90000)).
+
 
 -spec start_link(inet:socket(), atom(), shaper:shaper(),
                  non_neg_integer() | infinity) -> ignore |