[desc] Add node process function to use on single-chunk nodes

[Alxiice]

Warning

It would be better to merge this PR after #2845 because the logger is not available in process for now (as it's provided by chunk). This PR mentioned fixes this by setuping logging so that we can use it directly

Description

• Add a process function
• If there is no parallelization, then if processChunk has not been overrided, then process will be called

Examples

Because we don't have access to the chunk we can't use chunk.logger

import logging
logger = logging.getLogger("TestNode2")

def print_info():
    logger.info(f"Message with info    level ({logger})")
    logger.warning(f"Message with warning level ({logger})")
    logger.error(f"Message with error   level ({logger})")

class TestNode3(desc.Node):    
    inputs = [
        desc.ChoiceParam(
            name='verboseLevel',
            label='Verbose Level',
            description='''verbosity level (fatal, error, warning, info, debug, trace).''',
            value='info',
            values=['fatal', 'error', 'warning', 'info', 'debug', 'trace'],
            exclusive=True,
        ),
    ]

    outputs = [
        desc.File(
            name='outputFolder',
            label='outputFolder',
            description='outputFolder',
            value="{nodeCacheFolder}",
        ),
    ]

    def process(self, node):
        logger.setLevel(node.verboseLevel.value.upper())
        logger.info(f"> verboseLevel : {node.verboseLevel.value}")
        logger.info(f"> outputFolder : {node.outputFolder.value}")
        print_info()

However, after #2845 this won't be an issue because we could use logging normally :

[codecov]

Codecov Report

❌ Patch coverage is 95.83333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.08%. Comparing base (123c15a) to head (1be1fc5).
⚠️ Report is 3 commits behind head on develop.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
meshroom/core/desc/node.py	60.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2847      +/-   ##
===========================================
+ Coverage    79.00%   79.08%   +0.07%     
===========================================
  Files           51       51              
  Lines         6858     6889      +31     
===========================================
+ Hits          5418     5448      +30     
- Misses        1440     1441       +1     

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[cbentejac]

FYI: without the __test__ = False line, pytest tries to load the TestNodeA and TestNodeB classes because of the "Test" in their name, and fails as they have __init__ methods.

An alternative to using __test__ = False would be to rename the classes to not use the word "Test".

[cbentejac]

Approved but waiting for #2845 to be merged first.