sdbusplus: use shorter type aliases

The sdbusplus headers provide shortened aliases for many types.
Switch to using them to provide better code clarity and shorter
lines.  Possible replacements are for:
  * bus_t
  * exception_t
  * manager_t
  * match_t
  * message_t
  * object_t
  * slot_t

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I223d58649a21565678bd7ef78d955b30d3fd6d84
diff --git a/manager/manager.hpp b/manager/manager.hpp
index 2fbc7f2..ac00d76 100644
--- a/manager/manager.hpp
+++ b/manager/manager.hpp
@@ -76,7 +76,7 @@
      *  @param [in] bus       - sdbusplus handler
      *  @param [in] GroupMap - LEDs group layout
      */
-    Manager(sdbusplus::bus::bus& bus, const GroupMap& ledLayout) :
+    Manager(sdbusplus::bus_t& bus, const GroupMap& ledLayout) :
         ledMap(ledLayout), bus(bus)
     {
         // Nothing here
@@ -126,7 +126,7 @@
 
   private:
     /** @brief sdbusplus handler */
-    sdbusplus::bus::bus& bus;
+    sdbusplus::bus_t& bus;
 
     /** Map of physical LED path to service name */
     std::unordered_map<std::string, std::string> phyLeds{};