Why an Assay is a process sequence but a Run is a single process

[HLWeil]

Following a real life discussion, here are some keypoints:

Central question: Why does the Assay contain a sequence of processes, depicting multiple steps, but a Run is a single process by itself, even though it can also consist of multiple steps?

• A process is the execution of a single protocol
• For assay metadata, the inputs and outputs for each subprocesses are explicitly defined after the process is executed. The executed protocol does not give any input or output information whatsoever
• For runs, this is different, as the workflows they execute can already consist of strung-together sub-workflows (protocols). There the outputs of one sub-workflow is already defined as the input of the next sub-workflow. Only the initital inputs and finals outputs need to be defined for the execution of this top-level workflow (protocol)

i.e.

• an assay contains a sequence of processes each executing a single protocol
• a run is a single process executing a single protocol consisting of multiple sub-protocols

@muehlhaus @kMutagene