GUI spatial tab: allow branch colouring using results from other outputs

[shawnlaffan]

The spatial tab allows users to visualise results on the tree at the same time as they are viewing the map.

This is even more useful now with the addition of CANAPE. However, viewing the results of clade contributions, for example, needs these calculations to be run before the randomisation needed for CANAPE, as otherwise they are not available for display.

It would be useful if the index chooser had access to other outputs in the basedata (and possibly the project).

Relevant blog posts:
https://biodiverse-analysis-software.blogspot.com/2017/09/visualise-spatial-analysis-results-on.html
https://biodiverse-analysis-software.blogspot.com/2022/10/biodiverse-now-calculates-canape-for-you.html

Related tasks:

• Code (PR: GUI Spatial tab: support branch colouring using any spatial output across the project #903)
• Blog post