[WIP] ThemeInterface

# Implement ThemeInterface
[ ] ThemeInterface
[ ] ThemeRepositoryInterface
[ ] ThemeConfigReaderInterface
[ ] Add tests
[ ] DefaultTheme Class implements ThemeInterface
[ ] Read config
[ ] Get Theme config
[ ] Get Theme layouts
[ ] Get Theme colors
[ ] Get Theme textures
[ ] Set Theme layout
[ ] Set Theme color
[ ] Set Theme texture
[ ] Theme filter
[ ] Theme layout filter
[ ] Theme color filter
[ ] Theme texture filter
[ ] Call on create Theme
[ ] Call on change Theme