Collection of possible major release issues

[SteffenMeinecke]

This issue collects topics to discuss and tasks for future pandapower 4.0:

Tasks

• clean up import #1917
• consistency in naming: element, index, element_index, element_type, ... #1630
• Fundamental reorganization of element tables for more consistency? #1629
• Standard Type Library as DataFrames? #1624
• use nullable integer dtypes #1631
• Improved error handling #2458

[pawellytaev]

this one seems related and we should discuss it: #1553