sensors: split building from manager object

To increase testability, split out the building of sensors
from the sensor manager.  And this further splits out building
from a configuration file.

Tested: Verified code continued to build and link.
Tested: Ran on quanta-q71l board and it behaved as expected.

Change-Id: Ib63a11e1107b1864c3c370bba2bd9ef2effa42f3
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/sensors/manager.hpp b/sensors/manager.hpp
index d466039..a3e7420 100644
--- a/sensors/manager.hpp
+++ b/sensors/manager.hpp
@@ -32,18 +32,7 @@
         void addSensor(
             std::string type,
             std::string name,
-            std::unique_ptr<Sensor> sensor)
-        {
-            _sensorMap[name] = std::move(sensor);
-
-            auto entry = _sensorTypeList.find(type);
-            if (entry == _sensorTypeList.end())
-            {
-                _sensorTypeList[type] = {};
-            }
-
-            _sensorTypeList[type].push_back(name);
-        }
+            std::unique_ptr<Sensor> sensor);
 
         // TODO(venture): Should implement read/write by name.
         std::unique_ptr<Sensor>& getSensor(std::string name)
@@ -69,7 +58,3 @@
         sdbusplus::bus::bus _hostSensorBus;
 };
 
-std::shared_ptr<SensorManager> BuildSensors(
-    std::map<std::string, struct sensor>& Config);
-
-std::shared_ptr<SensorManager> BuildSensorsFromConfig(std::string& path);