[WIP] use built-in Docker init, remove tini

[meonkeys]

We no longer need tini with recent versions of Docker.

See:

• https://docs.docker.com/reference/cli/docker/container/run/#init
• https://github.com/krallin/tini?#using-tini

Tested and seems to work as expected when --init is included in docker run command line or init: true is included in the Docker Compose service stanza.

I think it's OK to exclude the -g argument (pass along signals to process group) since we only run the one node process, but I'm not certain.

Look for a correspoding change in the docs repo.

[meonkeys]

see https://github.com/actualbudget/docs/pull/486

[meonkeys]

From a Discord chat discussion: if people upgrade Docker containers and get this change, their containers will shut down more slowly (10sec by default, IIRC) until/unless --init is added to the docker run command line or init: true is included in their service stanza in their Docker Compose config file.

[billneftleberg]

Do we still need tini with recent Docker versions if --init or init: true works, and is it safe to skip the -g argument?