Configuration ini format

They now take configuration in the standard ini format.
Default configuration file is read off /etc/contrail/collector.conf and
/etc/contrail/query-engine.conf

One can override the values from the config file through command line option
as well. e.g. --DEFAULT.log_level=DEBUG

Use --help to see various options available. Package build also places the
default config files under /etc/contrail/.

When changes are made to the configuration file, the process must be _restarted_
to take effect. (e.g. service supervisord-analytics restart).