CWL workflow steps

[fmigneault]

Changes:

• Add CWL MultipleInputFeatureRequirement support.
• Add CWL SubworkflowFeatureRequirement support.
• Add CWL Workflow explicit schema validation of its steps.
• Remove "unknown" definitions in CWL requirements. Only fully defined and resolved definitions will be allowed. If an unsupported CWL requirement by Weaver must be provided (but is a valid definition supported by cwltool), it must now be provided through hints to succeed schema validation.
• Improve support of CWL output definition using loadContents to an outputBinding.glob reference to load the File contents into a string output.
• Improve support of CWL JavaScript expressions within intermediate steps of a Workflow to collect output results from relevant sources with better data manipulation flexibility.
• Modify signature of weaver.processes.wps_process_base.WpsProcessInterface to allow better reuse of the common operations shared by derived CWL Workflow steps implemented by ESGFProcess, Wps1Process, Wps3Process and OGCAPIRemoteProcessBase.
• Refactor ESGFProcess to use the common operations of CWL Workflow steps defined by WpsProcessInterface.

Fixes:

• Fix invalid CWL schema definition for ScatterFeatureRequirement that directly contained the corresponding fields scatter and scatterMethod, instead of the expected definition within a Workflow Step.
• Fix CWL requirements schema definition using OneOf and the discriminator property that could sometime drop a definition when it only contained an empty mapping {}, and that the corresponding requirement allows it.
• Fix weaver.wps_restapi.colander_extras.AnyOfKeywordSchema not allowing distinct JSON structure type to be combined simultaneously.
• Fix CWL Workflow not retrieving output results when returned directly as literal data from a remote Process.
• Fix CWL Workflow potentially failing tool resolution for a local step Process if hints where omitted.
• Fix CWL Workflow resolution of step requirements from one of the Weaver application types (i.e.: builtin, docker, ESGF-CWT, OGCAPI, WPS1) due to cwltool namespace adding a prefixed URI.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 79.89418% with 76 lines in your changes are missing coverage. Please review.

Project coverage is 85.76%. Comparing base (aae0904) to head (ee56c8d).

Files	Patch %	Lines
weaver/processes/esgf_process.py	0.00%	46 Missing :warning:
weaver/processes/wps_package.py	84.74%	15 Missing and 3 partials :warning:
weaver/wps_restapi/colander_extras.py	61.53%	2 Missing and 3 partials :warning:
weaver/processes/utils.py	42.85%	4 Missing :warning:
weaver/processes/wps_process_base.py	81.25%	2 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #649 +/- ## ========================================== - Coverage 85.78% 85.76% -0.02% ========================================== Files 79 79 Lines 18654 18846 +192 Branches 2862 2905 +43 ========================================== + Hits 16002 16163 +161 - Misses 1907 1927 +20 - Partials 745 756 +11 ```

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