add_table() method would be consistent w. other add_[attribute]()

[MichielVerCruysse]

Adding a table as follows
sdata.table = myTable
is inconsistent with the method for adding images, labels, points and shapes. I feel like an add_table method would be clearer.

[LucaMarconato]

Thanks @MichielVerCruysse for reporting this. We actually fixed this inconsistency but we haven't made a release yet. It will probably take a few more weeks until we cut one.

We took another approach: in #329 we remove the add_image(), add_labels(), ... methods and in the branch https://github.com/scverse/spatialdata/tree/multi_table we added support for multiple tables.

If you want you can already use these functions by installing the library from main or from the multi_table branch.