Similar to other openstack projects,
monasca-api should provide information
about request's context in the log information.
This is done by:
* implementing custom Request that creates context (oslo.context)
* changing logging configuration to use ContextLogFormatter
Since information like tenant-id can be
retrieved from the context, modified resource code to use
that.
Also moved 'limit' directly to request property.
Change-Id: I917fa2cba99dc668842fea0a62cda2cabd796d09
044f389848