Integrated Pipeline: added end-to-end tests for parsing rawdata-archive content with multiple workers

Integrated Pipeline: added a short sleep to mock processing in CalculationParsingFlowSpec to stabilize task distribution

Integrated Pipeline: added tests to verify interleaved processing of multiple file tress in ParsingResultsProcessingManager

-MessageProcessor has a new function "requiresMoreMessages" which is used to determine if
 the graph stage can finish cleanly once no more inbound messages arrive

Integrated Pipeline: basic implementation of MessageProcessorFlow (will replace existing graph elements)

-MessageProcessorFlow is an abstract graph element powered by an underlying MessageProcessor,
 it handles one-to-one, one-to-many and many-to-one processing stages all alike

Integrated Pipeline: added behaviour tests for MessageProcessor trait, ParsingResultsProcessingManager implements it

Integrated Pipeline: started introducing ParsingResultsProcessingManager to separate application logic from streams integration

Integrated Pipeline: moved path/treetype validation logic from Graph element to CalculationParsingEngine

Integrated Pipeline: ParsingResults now have an explicit field for the error message of failed parsing tasks

Integrated Pipeline: further rework of the CalculationParsingEngine tests to make them more flexible

Integrated Pipeline: refactored CalculationParsingFlow tests, added stream assertion for normal completion

Integrated Pipeline: ArchiveCleanUpFlow now removes temporary extracted files once all expected results passed through

Integrated Pipeline: merged parsing task/result messages into a single file to merge the start/end signals

-parsing and result signals now use the same start/end signal case classes to get rid of duplicate code
 and unnecessary transformations

-CalculationParsingFlow now uses the extractedPath field assigned by the ArchiveUnpackingFlow
-removed some tests for CalculationParsingFlow that are no longer needed

Integrated Pipeline: FileParsingTaskEndTree emitted by TreeParserFlow now includes the number of generated parsing tasks

-improved error messages given by findFirstMatchingStreamElement

Integrated Pipeline: element search assertion now takes matchers that work on a subset of the element stream only

-elements with non-compliant classes are automatically considered matching failures
-simplifies property matcher structure

Integrated Pipeline: skeleton implementation for ArchiveCleanUpFlow, simply forwards directory file tree based signals

Integrated Pipeline: CalculationParsingFlow test fixture inherits from StreamAssertions, renamed test sink/source