Expand version output to include library versions

- Add new 'extra_version' field for commands so that they can report extra info,
  like the version number of external modules.
- Added Splunk Python SDK version to the output of '--version'.

ksconf/__main__.py

@@ -107,7 +107,10 @@ def build_cli_parser(do_formatter=False):
             if error:
                 version_info.append("      {:15} {:10}  {}".format(name, m, error))
             else:
-                version_info.append("      {:15} {:10}  OK".format(name, m))
+                info = "      {:15} {:10}  OK".format(name, m)
+                if cmd_cls.version_extra:
+                    info = "{}   ({})".format(info, cmd_cls.version_extra)
+                version_info.append(info)
 
     # Common settings
     '''

ksconf/commands/__init__.py

@@ -310,6 +310,7 @@ class KsconfCmd(object):
     description = None
     format = "default"
     maturity = "alpha"
+    version_extra = None
 
     def __init__(self, name):
         self.name = name.lower()

ksconf/commands/restpublish.py

@@ -67,6 +67,8 @@ def _handle_imports(cls):
             return
         import splunklib.client
         g["splunklib"] = splunklib
+        import splunklib
+        cls.version_extra = "splunk-sdk {}".format(splunklib.__version__)
 
     def register_args(self, parser):
         # type: (ArgumentParser) -> None