R1:be00264ae74b

Make daemons perform file deletion

Summary:
Deletion is a possibly time-intensive process, especially with large
files that are backed by high-latency, chunked storage (such as
S3). Even ~200mb objects take minutes to delete, which makes for an
unhappy experience. Fixes T10828.

Test Plan:
Delete a large file, and stare in awe of the swiftness with
which I am redirected to the main file application.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

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