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/ncc-strategy.t.cpp b/tests/daemon/fw/ncc-strategy.t.cpp
index cc32201..a792404 100644
--- a/tests/daemon/fw/ncc-strategy.t.cpp
+++ b/tests/daemon/fw/ncc-strategy.t.cpp
@@ -40,7 +40,10 @@
 BOOST_AUTO_TEST_SUITE(Fw)
 BOOST_FIXTURE_TEST_SUITE(TestNccStrategy, UnitTestTimeFixture)
 
-using fw::NccStrategy;
+BOOST_AUTO_TEST_CASE(Registration)
+{
+  BOOST_CHECK_EQUAL(Strategy::listRegistered().count(NccStrategy::STRATEGY_NAME), 1);
+}
 
 // NccStrategy is fairly complex.
 // The most important property is: