storage_file_collection_time_utc not honored, instead midnight is default

[BrandtWoolf]

Currently the storage_file_collection_time_utc setting is not honored, instead the seconds setting is disregarded and its just sets the time to midnight utc.

Default Setting:

...
:workers:
  ...
  :worker_base:
    ...
    :schedule_worker:
       ...
       :storage_file_collection_time_utc: 21600
...

Current operation of adding the seconds to the current date being disregarded:

irb(main):061:0> at=21600
=> 21600
irb(main):062:0> Time.now.strftime("%Y-%m-%d #{at}").to_time(:utc)
=> 2019-03-22 00:00:00 UTC

Suggested changes to support adding the defined seconds to the beginning of the current day:

irb(main):061:0> at=21600
=> 21600
irb(main):063:0>Time.zone.today.to_time(:utc) + at.seconds
=> 2019-03-22 06:00:00 UTC

This was the simplest change but it might be worth adjusting the default setting to more align with other time settings and define it as x.seconds