Geo: Add Geo Name as Display name field on Node Card

Follow up for https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10755.

I think it's ok for this to not make 11.11 since https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10755 is functionally complete.

But there are a couple UX/frontend things that I'm separating out here to keep smaller iterations.

• @toon suggested to also validate max length in browser, which makes sense to me, though I don't know if we have a standard practice regarding this. => Already happening based on the models/geo_node.rb

• Display the geo node name field on each node in the Admin > Geo > Nodes index page. It's as important as the geo node URL. => !21876 (merged)

@kushalpandya @undefined

Proposed design