558 Add optional node-level memory constraint instead of rank-level constraint to loosen

[lifflander]

Fixes #558

[ppebay]

@lifflander we seem to have a confusion between the two types of object ids/indices now:

[LBAF_app] Writing single phase 0 to JSON files
multiprocessing.pool.RemoteTraceback: 
"""
Traceback (most recent call last):
  File "/Users/pppebay/miniconda3/envs/lbaf39/lib/python3.9/multiprocessing/pool.py", line 125, in worker
    result = (True, func(*args, **kwds))
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/IO/lbsVTDataWriter.py", line 279, in _json_writer
    serial_json = self._json_serializer(rank_phases_double)
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/IO/lbsVTDataWriter.py", line 251, in _json_serializer
    self.__create_tasks(
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/IO/lbsVTDataWriter.py", line 126, in __create_tasks
    if o.get_index() is not None:
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/Model/lbsObject.py", line 184, in get_index
    return self.__index
AttributeError: 'Object' object has no attribute '_Object__index'
"""

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/Applications/LBAF_app.py", line 693, in <module>
    LBAFApplication().run()
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/Applications/LBAF_app.py", line 623, in run
    self.__json_writer.write(
  File "/Users/pppebay/Documents/Git/LB-analysis-framework/src/lbaf/IO/lbsVTDataWriter.py", line 316, in write
    for file_name in results:
  File "/Users/pppebay/miniconda3/envs/lbaf39/lib/python3.9/multiprocessing/pool.py", line 870, in next
    raise value
AttributeError: 'Object' object has no attribute '_Object__index'

This should be resolved by PR #565 @lifflander

[ppebay]

Assigning @cwschilly to resolve the issues caused by the recent merges Tx

[cwschilly]

How should we handle the else condition of this block? (There is a pylint error because r_dst might not be defined)