regulators: Create configuration file parser

Create the initial version of the configuration file parser.  This will
parse the JSON configuration file that controls the phosphor-regulators
application.

This commit implements support for parsing the following JSON elements:
* root element in the config file (config_file.md)
* array of rules
* rule (rule.md)
* array of actions
* action (action.md)
* pmbus_write_vout_command (pmbus_write_vout_command.md)
* array of chassis (chassis.md)

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: Id5f239517e1828e475fa81e26c56b85f678920cb
diff --git a/phosphor-regulators/src/meson.build b/phosphor-regulators/src/meson.build
index b652f08..ef40cb9 100644
--- a/phosphor-regulators/src/meson.build
+++ b/phosphor-regulators/src/meson.build
@@ -4,6 +4,7 @@
 )
 
 phosphor_regulators_library_source_files = [
+    'config_file_parser.cpp',
     'id_map.cpp',
     'pmbus_utils.cpp',