Geo: Display Custom Avatars (user, project and group) in secondary nodes
Description
Custom avatars (not using gravatars) are not displayed in secondary Geo nodes. This happens because we are not replicating assets yet.
Proposal
We don't have assets locally in a secondary node, but we can use the same strategy we did in !302 (merged) and render images stored in the primary node.
Code change will probably be made in application_helpers.rb to override default behavior and switch to avatar path + join with primary node's root url.