pseq: Add support for UCD90160 EM configuration

Add power control support for receiving Entity Manager configuration for
a UCD90160 device and instantiating an object of that type.

Tested:
* Test where EntityManager information is available when application
  starts
* Test where EntityManager information is not available when application
  starts
  * Verify the EntityManager information is found later via
    InterfacesAdded events
* Test where xyz.openbmc_project.Configuration.UCD90320 interface is
  found
  * Verify UCD90320Monitor object is created
* Test where xyz.openbmc_project.Configuration.UCD90160 interface is
  found
  * Verify UCD90160Monitor object is created
* Verify chassis can be powered on without errors
* Verify chassis can be powered off without errors
* Verify pgood error is detected and logged

Signed-off-by: Jim Wright <jlwright@us.ibm.com>
Change-Id: Ibdb86db176971f27bbd2a998a39a0325997c6677
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/src/power_control.hpp b/phosphor-power-sequencer/src/power_control.hpp
index 660b90b..f623fd8 100644
--- a/phosphor-power-sequencer/src/power_control.hpp
+++ b/phosphor-power-sequencer/src/power_control.hpp
@@ -14,6 +14,7 @@
 #include <sdeventplus/utility/timer.hpp>
 
 #include <chrono>
+#include <string>
 
 namespace phosphor::power::sequencer
 {
@@ -172,7 +173,7 @@
      * Get the device properties
      * @param properties A map of property names and values
      */
-    void getDeviceProperties(util::DbusPropertyMap& properties);
+    void getDeviceProperties(const util::DbusPropertyMap& properties);
 
     /**
      * Callback to begin failure processing after observing pgood failure wait