Consistent semantics of removing/cancelling or deleting requests

[OscarSeip]

Ensure consistent semantics across lowFAT when using cancel/delete or remove buttons. In all cases, the request should not be removed from the system and any reserved funds must be returned to the fellows' budget.

[Kvglass]

There shouldn't be a delete option - we should be able to see the status of all requests. Rather than "cancel" should the fellow have the option to "withdraw" their request?