treewide: remove 'using namespace' from headers

Using namespace at global scope in a header file violates the cpp core
guidelines.  Quoting the guidelines:

  "Doing so takes away an #includer’s ability to effectively
disambiguate and to use alternatives. It also makes #included headers
order-dependent as they might have different meaning when included in
different orders."

For further reading:
https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rs-using-directive

The guidelines don't call out using using namespace from namespace
scope, but it is only marginally less problematic and still unexpected,
so this patch removes those as well.

The process used to do the update is roughly:

1 - git grep 'using namespace' **.hpp
2 - For each instance, remove the offending 'using namespace' line
3 - build
4 - add 'using namespace' to cpp files or fully resolve types in hpp
  files until the project builds again.

Further cleanup is possible - for example cpp files could be scrubbed
for unnecessary namespace qualification - this was not done here to make
review as simple as possible.

Change-Id: I4931f5e78a1b5b74b4a4774c035a549f4d59b91a
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/libpldmresponder/bios_config.hpp b/libpldmresponder/bios_config.hpp
index 8477628..18e13b0 100644
--- a/libpldmresponder/bios_config.hpp
+++ b/libpldmresponder/bios_config.hpp
@@ -77,7 +77,7 @@
      */
     explicit BIOSConfig(
         const char* jsonDir, const char* tableDir,
-        DBusHandler* const dbusHandler, int fd, uint8_t eid,
+        pldm::utils::DBusHandler* const dbusHandler, int fd, uint8_t eid,
         dbus_api::Requester* requester,
         pldm::requester::Handler<pldm::requester::Request>* handler);
 
@@ -134,7 +134,7 @@
 
     const fs::path jsonDir;
     const fs::path tableDir;
-    DBusHandler* const dbusHandler;
+    pldm::utils::DBusHandler* const dbusHandler;
     BaseBIOSTable baseBIOSTableMaps;
 
     /** @brief socket descriptor to communicate to host */
@@ -156,7 +156,7 @@
     BIOSAttributes biosAttributes;
 
     using propName = std::string;
-    using DbusChObjProperties = std::map<propName, PropertyValue>;
+    using DbusChObjProperties = std::map<propName, pldm::utils::PropertyValue>;
 
     // vector to catch the D-Bus property change signals for BIOS attributes
     std::vector<std::unique_ptr<sdbusplus::bus::match::match>> biosAttrMatch;