Add Dark mode C plugin to the official list

[pullitall]

Adds toolbar icons to instantly switch between light and dark mode with no restart required. Features an automatic mode that dynamically toggles your theme based on local sunrise and sunset times

[chcg]

@pullitall Plugin dll needs to be at the toplevel of the zip file

Dark Mode C *** REQUIRES Npp >= 8.0 ***
{'category': 'error',
 'details': '',
 'message': 'Dark Mode C: Zip file does not contain dark_mode_C.dll.'}

[pullitall]

Sorry, fixed the .zips into correct structure, added new checksums for new files.

[chcg]

@pullitall

Dark Mode C *** REQUIRES Npp >= 8.0 ***
{'category': 'error',
 'details': '',
 'message': 'Dark Mode C: Does not contain any version information.'}

Version info needs to be added similar to e.g.

https://github.com/npp-plugins/plugintemplate/blob/master/src/NppPluginDemo.rc