Added option to specify deploymentMode for SpringProcessEngineConfiguration

Added option to specify deployment mode of
SpringProcessEngineConfiguration when auto deployment resources are
specified.

* There is a new optional property deploymentMode in
SpringProcessEngineConfiguration;
* Default behavior is the same as currently implemented: all resources
are grouped in a single deployment;
* New options are single-resource (each resource in a separate
deployment) and resource-parent-folder (group resources into deployments
for each parent folder);
* Updated existing testcases and added some new resources to cover
various scenarios;
* Updated documentation in Userguide;