Create TemporarySubDirectory class

Create class that automatically creates and deletes a temporary
subdirectory.

The subdirectory will be located beneath the system temporary directory
(such as /tmp).

Change-Id: Id14d33b47658f144ad17c6741ec36f58492a88e2
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/meson.build b/meson.build
index da7a277..7d5dd11 100644
--- a/meson.build
+++ b/meson.build
@@ -157,6 +157,7 @@
     'gpio.cpp',
     'pmbus.cpp',
     'temporary_file.cpp',
+    'temporary_subdirectory.cpp',
     'utility.cpp',
     dependencies: [
         nlohmann_json_dep,