Merge topic 'tokio-uplift'

11b6848b handlers: use `tokio::task::spawn_blocking` to handle jobs
f7c21cf9 cargo: update the test suite to use tokio 1.0
fd436294 cargo: update json-job-dispatch
3ed0121b cargo: drop unnecessary features of `chrono`
9870621f cargo: remove `failure` direct dependency

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !302
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