New easier table notebook

Currently we explain how to work with tables with a notebook that has been reported being too technical.

We are considering moving the notebook to a technical section of the docs and instead make a new notebook showing a biological use case.

Here is a possible story from the notebook.

loading the data

• load data containing a segmentation (with a spatialdata-io reader)
• load some extra annotation from CSV files with increasing complexity, like having or not an header, missing row, multiple samples, etc (idea from @minhtien-trinh), showing how we can go from a CSV file to a AnnData table that is annotating an element

resegmenting

• resegment it with a simple algorithm not requiring heavy dependencies, but mention state of the art/recommended methods
• now show how to add this new segmentation to the SpatialData object

comparing the segmentations by spatial overlap

say that we had 2 segmentation masks, and each masks had a gene expression table

• show how to create 2 new tables (one for each segmentation mask), so that the original tables are filtered and reindexed to contain only the cells for which the 2 segmentation masks agree (spatial overlap)

Start with the existing tables notebook at tutorials/notebooks/notebooks/examples/tables.html and review how the current workflow is presented. Define a new biological-use-case notebook covering data loading, CSV annotations, resegmentation, adding the result to SpatialData, and comparing segmentations by spatial overlap. Done means the current technical notebook is moved to a technical documentation section and the new notebook provides the simpler narrative described here.