Add Julia base image to hub profiles

[betolink]

We need to elevate Julia to a first class citizen among the languages as is widely used in a lot of interesting projects.

[jules32]

+1 ! Several of our Champions teams - Nadia and Chris' groups in particular, are keen to experiment.

We can figure out the best approach to interface/call python libraries in Julia (like we do in R with reticulate). Here's a lead: https://github.com/JuliaPy/PyCall.jl