Deploy Cutscene Themes

[sigurdfdragon]

Makes use of Cutscene and Cutscene_Minimal themes for all scenarios in mainline that I am aware would benefit from it.

There seems to be a slight graphical hiccup when switching to Cutscene mid scenario in the third commit.

[CelticMinstrel]

With the second commit, if the user selects a different theme in preferences (for example, Classic), will that choice be honoured after the cutscene has ended.

If not, I'd suggest trying theme= - an empty attribute.

[sigurdfdragon]

@CelticMinstrel No, it wasn't honored. Thanks for the suggestion, that worked, and I've updated the commit. (and the wiki)

[sigurdfdragon]

I think I may remove part of the 2nd commit and all of the 3rd.
The third one because of the glitch, and both because for the non-SotA changes I'm not sure the cases warrant using them, and that's a decision best left for the campaign maintainers.

[Vultraz]

I think we should just merge the first commit for now.

[CelticMinstrel]

You can totally cherry-pick it and leave the PR open, if you want.

[sigurdfdragon]

I'll strip it down to the first commit and get it merged by the end of the week.
I'll pick the other two and stash them on a local branch of my repo copy.