Add a management command to close all connections

[shtlrs]

We are experiencing SSL errors in site which we think are due to the abrupt shut down of the django app.

A potential solution is to close all the connections before shutting the server down.

This will work in conjunction with this infra PR

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[shtlrs]

Yeah i noticed that once i had tested it, and was planning on changing the approach once you look at my suggestion in devoops