Get the remaining Harkonnen missions into the playtest

[reaperrr]

Since @MustaphaTR has all of them locally finished and ready for review, we should try to get them all reviewed and merged before the playtest branch-off (or before the 2nd playtest at the latest), as the first completed campaign would make for a nice advertiser.

• Harkonnen 5 D2K - Add Harkonnen 5 #14388
• Harkonnen 7 D2K - Add Harkonnen 7 #14426
• Harkonnen 8 D2K - Add Harkonnen 8 #14427
• Harkonnen 9a D2K - Add Harkonnen 9a #14429
• Harkonnen 9b D2K - Add Harkonnen 9b #14434

[reaperrr]

@MustaphaTR I think we'll get the remaining 4 reviewed and merged faster if you file the PRs all at once, since it allows us to review the next even if there are fixes/changes requested on the previous one.

[MustaphaTR]

Will do. I'm already onto sending the Har7.