Provide support for dynamically generated classes and __init__ options for IDE autocompletion, etc

[lbianchi-lbl]

• The way ProcessBlock subclasses are dynamically created through the @declare_process_block_class decorator is not compatible with tools that rely on static analysis of the code
• This includes pylint, which prompted my initial analysis of the problem (see FIXME for details), and ultimately required the creation of a (fairly complex) pylint plugin
• This also includes code IDEs, which severely limits the hints that can be provided to the user, in turn limiting the usability of IDAES as a platform
• Changing the current API to one that's more friendly to static analysis is not a viable option because of backward compatibility concerns and the amount of effort it would require
• To address this, I'm currently investigating a solutions based on type stub files (.pyi), which are companion files distributed alongside the code that allow providing type annotation information without modifying the actual code

[aspitarl]

There is a similar issue with pandas/xarray accessor methods and IDE autocomplete. Finding out about stubs led me to this recent package which solves that issue for xarray: https://pypi.org/project/accessor-stubs/. The project description gives a good overview of the problem. It fixed my autocomplete issue by overwriting the .pyi files in a package xarray-stubs in my virtual environment (thanks for the tip!)

Perhaps a similar solution could autogenerate the ProcessBlock stubs. I think it is a similar problem, as xarray accessors are defined using decorators. Though it looks as if there is a more generalized stub generation tool built into mypy.