Start configuration refactoring
Add TransportSettings

TransportSettings object wraps the underlying transport settings and is used by the Consumers.
This object can be initialzed from a configuration file, using fluent API or with default values.
UnitTest defaultConfiguation settings
Refactor Bus Configuration
Change default Configuration constructor

Constructor no longer tries to initialize settings from application configuration file.
Need to use Configuration.LoadSettings() explicitly load settings from configuration file.
Remove redundant null check from Publisher.ConfigureExchange
Add Bus.Publish()

Publish method will allow publishing from a bus instance using its TransportSettings.