Enhance XTS AS7 configuration

The current integration of XTS into AS7 as an AS7 extension allows optional configuration of the coordinator URL from the <xts/> element in the AS7 standalone configuration file. No other configuration options are currently supported.

XTS ought to support more precise configuration. IN particular, it ought to be possible to enable or disable deployment of coordinator, participant or client services independently and also to choose whether to deploy WS-AT or WS-BA services or both. This requires selectively deploying only the required web service endpoints, selectively executing the required initialization routines and selectively loading the required high level service implementations and context factory implementations.

The XTS implementation has already been factored so as to to support such discriminated bootstrapping. So this task only requires modifying the AS7 extension code to manage the relevant configuration information and install the relevant values into the XTS environment configuration beans before starting the XTS service.