Hide Job -> More info if there is no further info url provided

[hell03610]

When a user enters a job offer from https://vlctechhub.org/job/new/ she does not need to specify a further info url, as it is not mandatory.

However, we are always showing that field in the job page, with an empty link, which causes confusion (the user wonders: it is broken? some special charaters in the link that it can not be displayed correctly? - when actually there is no further info url available)

This happens for example on the job offer https://vlctechhub.org/job/board/ffd59c39-d803-49c9-aa1c-1f867a9baca6/

Suggested solution: if there is no further info url, dont show the section "Further info" at all.

[hell03610]

Finally solved in the api repo.