A container for the sendmatrix-server from sendmatrix.
To initialize matrix-commander-rs, start the init-service using docker compose up sendmatrix-server-init. Then
enter the container via perform the login procedure as per docker compose exec -it sendmatrix-server-init sh. This
gives you a shell so that you can setup matrix-commander-rs as per https://github.com/8go/matrix-commander-rs#usage.
(Usually someone would use matrix-commander-rs --login password --verify emoji, but you should read the documentation
nonetheless)
(Note: If you mount the persistent directories accordingly, you should only need to do this once)