Split postprocessing into data cleansing and enrichment

[gplssm]

Data cleansing

• Unplausible nominal power correction
• Filtering duplicates (expects raw data including all StatistikFlag A and B units)

Enrichment

• Add geom column and fill with data from lat/lon and PLZ

By doing this, parts of the code might be translated to python if that eases the process (as done for geom column creation).

[FlorianK13]

With v 0.11.0, cleansing is done when reading data into the database. Seperately, postprocessing scripts can then be applied later. They can be found in the github repository, postprocessing folder.