standalone workflow: parpost and aep_del

For the standalone workflows of parpost.py and aep_del.py:

Features:

• add them to the repo
• user definable weights for the AEP and LEQ
• user definable DLCs for the LEQ
• how are number of seeds now defined, is that auto derived?
• user definable wind speed distribution for the AEP and LEQ
• user inputs for the wind, electrical power channels, etc
• add plots

Bugs:

• aep_del.py assumes a [DLC] column that parpost.py does not generate
• aep_del.py has some crashes on the default environment on Sophia due to import statement from wetb