Allow reading configuration from JSON

JIRA: COMPOSE-3064
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

bin/pungi-koji

@@ -218,6 +218,12 @@ def main():
         kobo.log.add_stderr_logger(logger)
 
     conf = kobo.conf.PyConfigParser()
+    if opts.config.endswith(".json"):
+        with open(opts.config) as f:
+            conf.load_from_dict(json.load(f))
+        conf.opened_files = [opts.config]
+        conf._open_file = opts.config
+    else:
         conf.load_from_file(opts.config)
 
     compose_type = opts.compose_type or conf.get('compose_type', 'production')