Support multi power buttons with multi behaviors

For supporting more-than-one power buttons behaviors,
add new matches and instances by following json config.

This change is for multiple slots integrated on one chassis,
and each slot has button to control power status.

For example:
/xyz/openbmc_project/Chassis/Buttons/Power01 for button on slot1
/xyz/openbmc_project/Chassis/Buttons/Power02 for button on slot2

Moreover, support multi-level power control by json config,
chassis now can do action by corresponding pressing duration.

Tested:
Press buttons and check corresponding behaviors.

Change-Id: I7789f0367d5e846dd9e68f966ba0755fc916217a
Signed-off-by: Rush Chen <rush.chen.wiwynn@gmail.com>
diff --git a/inc/power_button.hpp b/inc/power_button.hpp
index 2cf28e4..f1e8ca2 100644
--- a/inc/power_button.hpp
+++ b/inc/power_button.hpp
@@ -29,7 +29,7 @@
 
 #include <chrono>
 
-static constexpr std::string_view POWER_BUTTON = "POWER_BUTTON";
+static constexpr auto POWER_BUTTON = "POWER_BUTTON";
 
 class PowerButton :
     public sdbusplus::server::object_t<
@@ -55,11 +55,11 @@
     void simPress() override;
     void simLongPress() override;
 
-    static constexpr std::string_view getFormFactorName()
+    static constexpr std::string getFormFactorName()
     {
         return POWER_BUTTON;
     }
-    static constexpr const char* getDbusObjectPath()
+    static constexpr std::string getDbusObjectPath()
     {
         return POWER_DBUS_OBJECT_NAME;
     }