Move timeMode property to manager

The current logic is to maintain the same attribute in manager and
epoch_base, the purpose of this commit is to merge this attribute
into manager for maintenance.

Also, Update the test/TestBmcEpoch.cpp file.

Tested: Built phosphor-time-manager successfully and UT passed.

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I05fea271d672bf12ecb722005023dfa6a2a980d1
diff --git a/manager.hpp b/manager.hpp
index 03229fb..02dd253 100644
--- a/manager.hpp
+++ b/manager.hpp
@@ -34,6 +34,16 @@
     Manager& operator=(Manager&&) = delete;
     ~Manager() = default;
 
+    void setTimeMode(Mode mode)
+    {
+        this->timeMode = mode;
+    }
+
+    Mode getTimeMode()
+    {
+        return this->timeMode;
+    }
+
   private:
     /** @brief Persistent sdbusplus DBus connection */
     sdbusplus::bus_t& bus;