Refactoring louloulibs and cmake

Use OBJECT libraries
Remove the louloulibs directory
Write FOUND variables in the cache

src/xmpp/auth.cpp

@@ -0,0 +1,8 @@
+#include <xmpp/auth.hpp>
+
+#include <utils/sha1.hpp>
+
+std::string get_handshake_digest(const std::string& stream_id, const std::string& secret)
+{
+  return sha1(stream_id + secret);
+}