Create regulators SetDeviceAction class

Create the SetDeviceAction class that implements the set_device action
in the JSON config file.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I31b8fbc144aa2cb2b4b3373fda559b0404d271cb
diff --git a/phosphor-regulators/test/actions/meson.build b/phosphor-regulators/test/actions/meson.build
index 8c3d2b8..d6821de 100644
--- a/phosphor-regulators/test/actions/meson.build
+++ b/phosphor-regulators/test/actions/meson.build
@@ -1,6 +1,7 @@
 test('phosphor-regulators-actions-tests',
      executable('phosphor-regulators-actions-tests',
                 'action_environment_tests.cpp',
+                'set_device_action_tests.cpp',
                 dependencies: [
                     gmock,
                     gtest,