GitHub download fallbacks for applicable mods

[HebaruSan]

In KSP-CKAN/CKAN#3877 we added the ability to list multiple download hosts per mod. This was released in CKAN v1.34.0 about 17 days ago. KSP-CKAN/NetKAN#9882 was the first usage of this about 15 days ago, and so far there have been no reports of problems.

Now all KSP2 mods that have GitHub repos with releases with assets have both SpaceDock and GitHub downloads listed. One mod that formerly only had a GitHub link now has a SpaceDock link as well. In all cases the GItHub section is listed before SpaceDock to account for SpaceDock's lower reliability and typically slower download speeds.

x_version_edit is used to create consistent version strings as needed (typically to remove a v prefix on GitHub that is absent from SpaceDock).

x_netkan_override is used to simulate the current value of SpaceDock's game version compatibility field for GitHub as needed. I think we should make this unnecessary by updating netkan.exe to merge game versions more intelligently, but I wanted to get this set up with the current code first. An alternative approach would be to remove the $vref from the GitHub section, but this isn't great practice and would generate warnings about swinfo.json existing without a $vref.

These mods have inconsistent latest versions between the two hosts, which causes inflation to fail or trip the auto-epoch logic, so they're omitted: HUMANS, IWishTheyMadeUICustomizable, K2D2, KerbalView, LazyOrbitBoosted, MicroEngineer, NodeManager, SORRY, ShowKSP2Events, CustomFlags, Starhopper, SkipSplashScreen, WASDForVAB.

SORRY and Starhopper are not included here because their swinfo.json files' invalid version_check links cause inflation errors.

Note that the spec_version is updated, so if users complain about not seeing the latest updates for any of these mods, make sure they're on the latest CKAN.

[cheese3660]

Custom flags, k2d2, and show ksp2 events failed?

[HebaruSan]

Oops, the cause of the installation error is indeed compatibility, but it's not the build ID thing. It's that the validator is always using the latest version, because we can't generate a valid KSP_x64.exe file containing a given version on the fly.

https://github.com/KSP-CKAN/CKAN/blob/71ee3196e5da4439aea4019f818d6e0f587d8c7f/Core/Games/KerbalSpaceProgram2.cs#L201C33-L209

For now this is OK, but it would be nice to have a proper way to set the game version for fake KSP2 instances.