UpdateManager configuration

- Implemented UpdateManagerConfiguration class to store the
configuration data specific to UpdateManager
- This class can be serialized and de-serialized into/from xml file.
- UpdateManager initializes the configuration from
UpdateManagerConfig.xml file if present in Dynamo installation,
otherwise by default it will point to production servers for
UpdateFileLocations and Signature file location.
- In Debug build it creates UpdateManagerConfig.xml file if not present
and saves the default configuration data. The same file can be used to
redirect the update location to the dev S3-bucket from a release build.
Addressing review comments
Adding testcase for UpdateManagerConfiguration
Merge pull request #2663 from Conceptual-Design/UpdateManager

UpdateManager configuration
Merge pull request #2757 from DynamoDS/master

Cross merge pull request #2663