Datasets: Option to provide Platform logo for third-party / offsite download platforms (vs. Study/org logo)

[christinerogers]

For datasets, distribution platform can be valuable to distinguished from the source study/org with branding.
It would be ideal if the big green "download with Datalad" button would be replaced with a "Download via EEGNet" logo-button.

related to -- CONP-PCNO/conp-dataset#885

EEGNet will have 7+ datasets to contribute entries for (spring 2024) and may be a special case as part of CONP, but it would be very useful to the CONP-EEGNet-BrainCanada relationship for a few reasons:

a) EEGNet is the vehicle for distribution and annotation not collection (unlike C-BIG even), and we want it to be seen as a distinct (and related) hub.

We also don't love the EEGNet logo appearing on the left side of each dataset (currently) because:

b) EEGNet didn't fund the collection or the research collaboration, just the distribution

c) Prefer putting data authors' own study / institution logo at left so that the (geographic) diversity and span of EEGNet datasets is evident.

This distroLogo of downloadPlatformLogo could be easily provided with and mentioned in the DATS.json

cc @GHPBZ from meeting May 6