UI theme settings

The theme settings offers the following options:

• Font size, with sizes for mobile phones or tabs.
• Alternative themes, to choose from dark/light or system-defined.
• Theme color, the main color used throughout the app.
• Button styles, choose from 11 styles. Suggest new ones if you feel like it!
• Tab style, at the top or bottom or completely hidden.
• Tab font size, should you want to customize it to your liking.
• Application colors, for user-installed, system-installed and Linux-kernel processes, those colors are used to highlight apps category.
• Icons theme, either material, 3D or theme-color-tinted 3D.