feat(mongodb-runner): add programmatic api for mongodb-runner

[baileympearson]

Description

I've been tinkering around with a vscode extension wrapper for mongodb-runner. The package currently only exports the cluster helpers but does not provide a programmatic interface to the functionality contained in cli.ts.

I pulled logic for ls, start and stop into standalone, exported functions so that I can consume them in my vscode extension without running bash commands using the runner's CLI. I understand if there's a desire to keep the API of this package slim and if we don't want to export the standalone helpers. If that's the case, I would be okay with keeping them as standalone functions but not exporting them from the index. I'm happy to import from the runner-helpers.ts file directly, this is just a toy project.

Along the way, I discovered that if I restarted my computer, mongodb-runner ls displays clusters that have been terminated. I also added a prune command, both to the programmatic exports and the runner's CLI, that attempts to connect to every instance in the runner's runnerDir and removes all entries for clusters that cannot be connected to.

Open Questions

Checklist

• I have signed the Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)
• New tests and/or benchmarks are included
• Documentation is changed or added