feat: refactor the appearance preferences for simplification.

[Allsochen]

Refactor the appearance preferences for simplification. There has been a lot of discussion about the issue of complex appearance preferences. You can check out this post.

• All complex UI appearances will be replaced by the appearance model and appearance size.
• Options will be categorized under various tabs or advanced button.
• Support white and black themes, and can automatically switch according to the system theme.
• Support displaying the title under the icon in app icons mode.
• Use new style settings UI like syteme settings at macOS.

Here is the snashoot of preferences:

Here is the snapshot of UI:

• Thumbnail Light theme
  

• Thumbnail Dark theme
  

• App Icons Light theme
  

• App Icons Dark theme
  

• Titles
  

[SupremeRubisco]

This looks awesome!