Refactor: Pass "CommandLineOptions" to CSettings::Load by reference

[pljones]

Short description of changes

Pass "CommandLineOptions" to CSettings::Load by reference

CHANGELOG: SKIP

Context: Fixes an issue?

N/A

Does this change need documentation? What needs to be documented and how?

No

Status of this Pull Request

I was using it in my main build but I split it out to make it easier to raise the PR. I'll use it in my (GUI) client and (headless) server for today.

What is missing until this pull request can be merged?

Review.

Checklist

• I've verified that this Pull Request follows the general code principles
• I tested my code and it does what I want
• My code follows the style guide
• I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• I've filled all the content above

[ann0see]

We should check that this doesn't cause side effects. In the code later down (needs code reading).

[pljones]

It shouldn't have any effect: the value is (well, should be) used only read-only in the code.

[ann0see]

Looking at the code, we do just use it with .contains, so everything is fine - as it should be.