fw: refactor Strategy registry

Strategy registry is moved into Strategy class.
Strategy instantiation logic is implemented in Strategy::create.
These are in preparation of supporting Strategy parameters.

refs #3868

Change-Id: If36a08ad25a00a7008a5eccc8cfe4f6c63638676
diff --git a/tests/daemon/fw/multicast-strategy.t.cpp b/tests/daemon/fw/multicast-strategy.t.cpp
index 1b8afcb..a5255b5 100644
--- a/tests/daemon/fw/multicast-strategy.t.cpp
+++ b/tests/daemon/fw/multicast-strategy.t.cpp
@@ -38,6 +38,11 @@
 BOOST_AUTO_TEST_SUITE(Fw)
 BOOST_FIXTURE_TEST_SUITE(TestMulticastStrategy, BaseFixture)
 
+BOOST_AUTO_TEST_CASE(Registration)
+{
+  BOOST_CHECK_EQUAL(Strategy::listRegistered().count(MulticastStrategy::STRATEGY_NAME), 1);
+}
+
 BOOST_AUTO_TEST_CASE(Forward2)
 {
   Forwarder forwarder;