refactor wps-process for workflow steps

[fmigneault]

Summary

• fix workflow collect output glob (fix CWL workflow outputs within nested binding not handled #371)
• refactor wps-process in workflow (reuse staging operations)

Changes

• No change.
• Refactor Workflow operation flow to reuse shared input and output staging operations between implementations.
  Each new step process implementation now only requires to implement the specific operations related to deployment,
  execution, monitoring and result retrieval for their process, without need to consider Workflow intermediate staging
  operations to transfer files between steps.
• Refactor Wps1Process and Wps3Process step processes to follow new workflow operation flow.
• Add builtin process file_index_selector that allows the selection of a specific file within an array of files.
• Add tests to validate chaining of Workflow steps using different combinations of process types
  including WPS-1, OGC-API and builtin implementations.
• Move CWL script examples in documentation to separate package files in order to directly reference them in
  tests validating their deployment and execution requests.
• Move all tests/functional/application-packages definitions into distinct directories to facilitate categorization
  of corresponding deployment, execution and package contents, and better support the various Workflow testing location
  of those files with backward compatibility.

Fixes

• No change.
• Fix handling of CWL Workflow outputs between steps when nested glob output binding are employed
  (resolves CWL workflow outputs within nested binding not handled #371).
• Fix resolution of builtin process Python reference when executed locally within a Workflow step.
• Fix resolution of process type WPS-1 from its package within a Workflow step executed as OGC-API process.
• Fix resolution of WPS1Requirement directly provided as CWL execution unit within the deployment body.
• Fix deployment body partially dropping invalid executionUnit sub-fields causing potential misinterpretation
  of the intended application package.
• Fix resolution of format reference within CWL I/O record after interpretation of the loaded application package.
• Fix missing WPS endpoint responses in generated OpenAPI for ReadTheDocs documentation.
• Fix and improve multiple typing definitions.

[dbyrns]

That is a very welcomed refactor!

[dbyrns]

Given that you'll fix the monitor interface implementation (bool part), there is nothing more blocking this PR.