Update Spearhead 1944 (SPE) compatibility for v1.1 release

[Drofseh]

When merged this pull request will:

• Add support for new Mortain terrain
• Add PRC-77 to Milice radio backpack
• Add custom radio configs to new armoured cars, tanks, tank destroyers, etc.
• Fix some small issues with configs and stringtable

[Drofseh]

configs look fine

I'm not thrilled about adding new vehicles in a compat, but I think I understand why it's being done

The new vehicles should be in their 1.1.1 update, they didn't have time for them in 1.1

[jonpas]

@Drofseh Needs conflict resolution, then good to merge.

[Drofseh]

@jonpas deconflicted

[Drofseh]

@jonpas or @PabstMirror can this be merged? It's been a few weeks now since SPE updated and the new terrain isn't supported until this PR is released.