Expand conf namespace

Put rest of conf.hpp in the conf namespace. This is
largely a sed replace, and wrapping from_json in
conf namespace as it failed to build.

Change-Id: I9fe5c7b2fface44618c43af2367035afc39bcb64
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/dbus/dbuspassive.cpp b/dbus/dbuspassive.cpp
index 206adbe..ee165b9 100644
--- a/dbus/dbuspassive.cpp
+++ b/dbus/dbuspassive.cpp
@@ -27,7 +27,7 @@
 
 std::unique_ptr<ReadInterface> DbusPassive::createDbusPassive(
     sdbusplus::bus::bus& bus, const std::string& type, const std::string& id,
-    DbusHelperInterface* helper, const SensorConfig* info)
+    DbusHelperInterface* helper, const conf::SensorConfig* info)
 {
     if (helper == nullptr)
     {