Finishes #5128 (Paygrade defines) & Fixes Syndie ID

[realforest2001]

About the pull request

As title. This PR continues my work from #5128 and adds the defines for PMCs, Mercenaries, VAI and TWE.
I have also changed how the global lists for highcommand (both USCM and WY) work and have made a new global list of all USCM officers to allow for easy reference in #5202.
To do the above I have added a default_faction var on paygrades, along with a variable to indicate if a paygrade refers to an "officer" or not, and if the officer is a "flag" officer, for senior leadership.
I have also updated the Syndicate ID card to work properly.

Explain why it's good for the game

Testing Photographs and Procedure

Screenshots & Videos

Put screenshots and videos here with an empty line between the screenshots and the <details> tags.

Changelog

🆑
add: Adds paygrade defines for PMCs, VAI, Mercenaries and TWE.
code: Adds code to populate reference lists for certain paygrades.
fix: Fixes PMC synth not using the correct grade.
add: Syndicate ID card repathed and works with paygrades.
/:cl:

[fira]

Looks good to me at a first pass

[github-actions]

This PR has been inactive for long enough to be automatically marked as stale. This means it is at risk of being auto closed in ~ 7 days, please address any outstanding review items and ensure your PR is finished, if these are all true and you are auto-staled anyway, you need to actively ask maintainers if your PR will be merged. Once you have done any of the previous actions then you should request a maintainer remove the stale label on your PR, to reset the stale timer. If you feel no maintainer will respond in that time, you may wish to close this PR youself, while you seek maintainer comment, as you will then be able to reopen the PR yourself

[cm13-github]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[cm13-github]

Conflicts have been resolved. A maintainer will review the pull request shortly.

stale