docker-dev: Refresh save code now statuses periodically

Without the following, as currently, the fresh new build from swh.web 0.0.302 onward, new save code now requests are not updated anymore through the ui. The following makes sure the status are updated periodically (15s).

This simply loops through indefinitely and periodically updates in db the save code now request statuses. As installing a cron was deemed unnecessary [1]

This is the equivalent of what's been deployed in production [2]

• [1] !242 (closed)

• [2] swh/infra/puppet/puppet-swh-site!95 (closed)

Related to T3280

Test Plan

docker-compose up, do some save code now requests and check the status gets updated when browsing through pagination:

$ swh-doco exec swh-web /bin/bash
+ cd /home/tony/work/inria/repo/swh/swh-environment/docker
+ docker-compose -f docker-compose.yml -f docker-compose.override.yml exec swh-web /bin/bash
root@8b20f39d055c:/# tail -f /tmp/refresh-statuses.log
...
Successfully updated 2 save request(s).
Thu Apr 29 08:48:01 UTC 2021
Nothing to do.
...

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Migrated from D5641 (view on Phabricator)