feat: load default template at startup if available in .fluidd-theme folder

[HelgeKeck]

feat: Loading a default template at startup if available

So i want to load a default template json file at the first app start, same files that come from the backup and restore feature, This PR isnt really working, but i hope to get some help here.

Problem at is that the getCustomThemeFile doesnt return any root files files for any reason and i cant find out why.

Signed-off-by: Helge Keck [email protected]