regulators: Add/install config files

Add a `config_files` directory to contain all JSON configuration files
and install all directories/files it contains to
`/usr/share/phosphor-regulators/`.

Tested:
    All directories/files contained are installed
    Installed configs are in /usr/share/phosphor-regulators

Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
Change-Id: I3d67adcd12dd5e05ea333001e9dbb023957551b4
diff --git a/phosphor-regulators/meson.build b/phosphor-regulators/meson.build
index 82a23ee..cd2c39c 100644
--- a/phosphor-regulators/meson.build
+++ b/phosphor-regulators/meson.build
@@ -1,3 +1,7 @@
+install_subdir('config_files',
+    strip_directory: true,
+    install_dir: get_option('datadir')/'phosphor-regulators')
+
 subdir('src')
 
 if get_option('tests').enabled()