General cleanup etc around properties and substitution

* Move pre-context init of JobParameters support out of ThreadLocalClassloaderBeanPostProcessor
* General cleanup in BatchPropertyBeanPostProcessor, move artifact type checking into classifer class, minor naming updates
* Refactor BatchPropertyContext to use different data structures for different types of properties and provide named accessors
* Remove path based artifact scoping support
* Make sure expressions are parsed when resolving properties directly from XML
* Update property tests
* Move registration of jobProperties bean into the JsrNamespaceUtils
BATCH-2095: Change JSR version of Split to execute flows in separate threads.