[Windows] Add user writeable fonts folder

[Rouven Hi!]

Hey guys,
since windows 10 there is a user writable location for fonts: %localappdata%\Microsoft\Windows\Fonts.
Might be worth adding it.

There is also a constant in the windows create for it:
windows::Win32::UI::Shell::FOLDERID_Fonts

Greetings

Resources:

• https://answers.microsoft.com/en-us/windows/forum/all/windows-10-fonts-folder/40616542-c0a4-417a-838e-3eab4294d825
• https://microsoft.github.io/windows-docs-rs/doc/windows/Win32/UI/Shell/constant.FOLDERID_Fonts.html

[soc]

Sorry, sadly fonts dirs on Windows don't work the way one would hope. :-/

See #37 (comment).