add module for working with spatialdata

[sophiamaedler]

Add an additional module scportrait.spdata that contains functions to execute frequent operations with spatialdata.

Proposed structure:
spdata
- write → simplified wrapper functions to add new elements to an existing spatialdata object
- filter/tranforms → perform certain operations on existing spatialdata objects

The functions in this module should not implement new features for spatialdata but instead reduce the code overhead for doing things that are already possible in spatialdata so that they remain accessible even to inexperienced programmers.

This module should not replace the scportrait.filehandler capabilities, but should instead be the location for most of the code located there currently so that within the filehandler only the existing methods are executed with the required parameters to be compatible with the established standards within scportrait.