hiring: Change general frontend role to be Cloud specific

Created by: tsenart

We decided to move towards team specific roles, so this closes that gap.

@felixfbecker, @jeanduplessis: I left the interview process intact, since I think the interviewers listed can do the best job at assessing a frontend candidate, but if we want to move to an offer stage, I'd want the candidate to meet a few teammates of the Cloud team. Does this make sense?

@withdavidli: We need to open a role in Lever and link to it in the job page. Can you help with this?