Update public datasette instance after rebuild

[danyx23]

Currently, there is a (broken) cronjob on the analytics server that is supposed to build the sqlite file and then does a dummy git commit to owid-datasette and pushes this. We want to get rid of analytics soon and so this should instead be done in the datasette LXC container instead.

Instead of doing dummy commits to trigger redeploys, the digital ocean API should be called to trigger a restart of the owid-public container after the sqlite file has been uploaded.

When this is done, the datasette folder on analytics and the cronjob can be deleted