Better Docker Support, Custom Storage Options

[belthesar]

Hi! This PR adds the following:

• Docker container support.
  • The readme mentioned Docker support, but no Dockerfile existed in the project. This adds it.
• Optional settings to specify the storage path for History DB, Cookies, and Output Directory.
  • This is largely useful for Docker-based execution, but could be useful for others as well.
• Settings cleanup to gracefully handle when not being executed in a context without OCI style secrets
  • When executed outside of a context that exposes secrets via /run/secrets, ie: locally via uv, Podman, etc, pydantic_settings would throw an error that it could not read from the path. This is now handled gracefully.

Open to feedback!