Add guide options to vis_grid_clus()

[lahuuki]

Add options for guides in vis_grid_clus(guides = c("all", "last", "none")). These options help make multi-sample plots less cluttered.

All is default - plots legends for ALL samples
vis_gene_clus_all.pdf

last plots the guide for only the last plot
vis_gene_clus_guide_last.pdf

none plots none of the guides, but exports a guide on the next page of the pdf file, helpful for placing by hand when building polished plots
vis_gene_clus_guide_none.pdf

Other changes:

• replaced ... with title_suffix arg that is better defined and prevents unexpected behavior in vis_*() funcitons
• changed default sort_clust = FALSE

[lcolladotor]

In the next few weeks let's try to find some time to resolve this one @lahuuki. I think that what was pending were some changes to make this work also on the shiny apps (aka spatialLIBD::run_app()), right?