* Fix s3-storage migrate and shell: container needs attachment to postgres network also

* Connect to s3-storage-provider migrate to multiple networks in multiple steps

Multiple `--network` calls lead to:

> docker: Error response from daemon: Container cannot be connected to network endpoints: NETWORK_1 NETWORK_2.

* Connect to s3-storage-provider shell to multiple networks in multiple steps

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Co-authored-by: Slavi Pantaleev <slavi@devture.com>

It's the same as `matrix_docker_network` for now, so this practically
doesn't change anything.