CLI hangs if Docker isn't running

[bamurtaugh]

I opened https://github.com/microsoft/vscode-remote-release/issues/8801 and thought the dev container CLI overall wasn't working at the moment for me since commands kept hanging. I realized the Docker engine was paused on my machine, and once I started running it, the CLI works.

It'd be really helpful to notify users Docker isn't running or installed on their system, rather than silently hanging.

[amaltson]

My personal experience was that it threw the following error when Docker wasn't running:

$ devcontainer up --workspace-folder .
[0 ms] @devcontainers/cli 0.52.1. Node.js v18.18.2. darwin 22.6.0 arm64.
{"outcome":"error","message":"Command failed: docker ps -q -a --filter label=devcontainer.local_folder=/Users/pfq501/work/oss/vscode-remote-try-rust --filter label=devcontainer.config_file=/Users/pfq501/work/oss/vscode-remote-try-rust/.devcontainer/devcontainer.json","description":"An error occurred setting up the container."}