Add era5 examples as python scripts

[uvchik]

Add Python examples

• Download era5 data (single location and bounding box)
• process single location with windpowerlib
• process single location with pvlib
• process bounding box

[birgits]

I would call the function processing_multiple_locations. Same goes for the file name which I would change to ..._multiple_locations.py.

[p-snft]

Second.

[birgits]

I find the function name confusing. It sounds like the examples are downloaded in the function. I would either just call it download_era5_multiprocessing or download_era5_multiprocessing_example.

[p-snft]

If I get it right, this is parallel download rather than "multi processing", am I right?

[birgits]

I think the oedialect is needed to download open_FRED weather data. Shouldn't we keep this as a requirement? I see the weather data download as an essential functionality of the feedinlib.

[birgits]

Thank you @uvchik for picking up work on the feedinlib again and adding new functionality to the examples, especially the multiprocessing parts which are quite useful. However, I think we need to discuss whether we want to provide example notebooks or python files, because in my opinion having both leads to an unnecessary maintenance overhead.
I prefer notebooks as they are an easy entry point for people who don't know python very well, they can be nicely included in the documentation and we can offer them on binder so people can use the feedinlib without having to install it, if they just want to try it out (btw, did you take out binder @uvchik?). Furthermore, they can be converted to python scripts if someone prefers them, so I don't see the advantage of having additional python scripts. What's your opinion on that @oemof/feedinlib people?

[p-snft]

If I get it right, this is parallel download rather than "multi processing", am I right?

[p-snft]

Second.

[p-snft]

At the top, you talk about time zones. Maybe go from 2016-12-21 to 2018-01-01 to emphasize that point.