Fix some docker instructions to point to new wiki page

[jayjb]

Proposed changes

Makes some of the Docker usage for OpenCanary more helpful and clear. Points folks at the new wiki page for Docker.

Types of changes

What types of changes does your code introduce to this repository?
Put an x in the boxes that apply

• Documentation Update

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• Lint and unit tests pass locally with my changes (if applicable)
• I have run pre-commit (pre-commit in the repo)