Add worker profiles

[THardy98]

What was changed

This change adds the ability to specify a --worker-profile in the Omes CLI, a string key that selects a worker configuration specified in code.

The value is passed as an env var to the language worker processes. I chose an environment variable to avoid having to add a flag to each worker's CLI parser (it's a string that doesn't need parsing and I think we want to minimize the parser/flag plumbing code).

Why?

This pattern avoids having to create worker option flags for each worker knob we want to expose. Instead, we can specify these programmatically, as was already possible with the SDK.

The trade-off is that worker configuration lives in code, changing the configuration of a worker requires creating a new profile (which then can be switched at call time by specifying that new profile).

In the future, we may consider adding something akin to --worker-config-json flag to Omes, where users could specify arbitrary JSON to customize worker options in their test/project. That way worker-profile allows for shared worker configs between tests/projects, while --worker-config-json provides flexible, test/project-specific configuration.

Checklist

1. Closes

2. How was this tested:

3. Any docs updates needed?