Create roadmap diagrams for spatial workshop

Similar to the roadmap diagrams we have for intro and advanced scRNA-seq, we should have analogous diagrams for spatial (single-sample analysis only at this time).

Miscellaneous thoughts I have that aren't fleshed out yet but want to record them to flesh out soon!
- I'd expect a diagram to have import, filtering, normalization and then a branch either to reduced dimension & clustering or to SVGs, or to deconvolution
- That said deconvolution takes in raw counts, not logcounts, so be careful to not mislead here
- So we want a separate diagram for low-res vs high-res techologies? Similarly, within high-res we are now introducing both image-based and seq-based techs. Are these separate or not? I imagine there is definitey at least one separate item here - maybe a high-res with two subdiagrams...

This may be broken into subissues.