Refactor D-Bus object

- The intent behind this commit is to refactor D-Bus, and abstract
  the bus, getService, getProperty and other methods into the utils
  file, and other file operations D-Bus only need to include
  uitls.hpp.

- We can also continue to add other general methods such as
  setPropery, getSubTree in the utils file in the future.

- Also, removed redundant files(occ_finder.hpp and occ_finder.cpp).

Tested: built openpower-occ-control successfully and worked.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I53e61e30a76173c154a9f47fc122936468abbc4b
diff --git a/pldm.cpp b/pldm.cpp
index 39437ad..729f292 100644
--- a/pldm.cpp
+++ b/pldm.cpp
@@ -73,6 +73,7 @@
     {

         PdrList pdrs{};

 

+        auto& bus = utils::getBus();

         try

         {

             auto method = bus.new_method_call(

@@ -244,6 +245,7 @@
     {

         PdrList pdrs{};

 

+        auto& bus = utils::getBus();

         try

         {

             auto method = bus.new_method_call(

@@ -284,6 +286,7 @@
 

     uint8_t instanceId{};

 

+    auto bus& = utils::getBus();

     try

     {

         auto method = bus.new_method_call(