Feature request: Theming improvements

[sevonj]

Is your feature request related to a problem? Please describe.
The theming function has unrealized potential.

Describe the solution you'd like

• The main proposal:

  • Add some built-in themes. For example, some users might prefer amoled dark theme to the default one.
  • Selecting themes separately: "Use Theme X for light mode, use Theme Y for dark mode"
  • Use the custom color editor as a theme option.
  • Semantic color names. Removes a lot of guesswork and allows better control. For example, meta1, meta2, and meta3 for the three shades used for meta block text. Same for backgrounds, markdown, etc.

• Bonus:

  • Let admins choose default themes, and add their own. This is possible on lemmy-ui, and seem to be used a lot.

Describe alternatives you've considered
-

Additional context
Add any other context or screenshots about the feature request here.

[Xyphyn]

Working on everything except semantic color names, as the colors are dynamically generated and may be used for multiple things, and it would be hell to name all of them