Add GitHub handles for instructors on training.bioconductor.org

[mblue9]

Flagging idea of @rcastelo raised in Bioconductor training meeting 14th Oct 2024 (notes) - we could add GitHub handles to Bioconductor instructors, similar to how they’re displayed on The Carpentries site.

To-Do:

• Check if we can access this info from The Carpentries for existing Carpentries instructors, or consider reaching out to instructors directly (cc @tobyhodges, @elletjies).