add clang-tidy

This commit implements a clang-tidy file, and makes some changes to get
it to pass.  Most changes are naming or mechanical in nature.

Tested:
Clang-tidy now passes.

Signed-off-by: Ed Tanous <ed@tanous.net>
Change-Id: Ia441e4801b6c8725421d160c531c5df141f255d4
diff --git a/include/ExternalSensor.hpp b/include/ExternalSensor.hpp
index bf3e885..fd36bb0 100644
--- a/include/ExternalSensor.hpp
+++ b/include/ExternalSensor.hpp
@@ -18,7 +18,7 @@
                    std::shared_ptr<sdbusplus::asio::connection>& conn,
                    const std::string& sensorName,
                    const std::string& sensorMeasure,
-                   std::vector<thresholds::Threshold>&& _thresholds,
+                   std::vector<thresholds::Threshold>&& thresholds,
                    const std::string& sensorConfiguration,
                    const double& maxReading, const double& minReading,
                    const PowerState& powerState);