[DRAFT] Centralize Styling to allow for Themes

[Zoooombie]

Fixes #535 (to some degree).

This is a draft because I have not done everything yet (I have not touched the calcs tab at all for example). Additionally some parts I could not figure out what they did, so I left them as is.
Open to feedback and help with understanding missing parts.

Description of the problem being solved:

Currently most colors and fonts are defined inline when drawing anything. This means color definitions are scattered across the code base making changing the theme of PoB a nightmare. I propose a CSS inspired approach where colors are defined in one central location with drawing logic referencing these through abstracted names (e.g. 'button_background' instead of #000000 in button definition). This way we can change what 'button_background' as a color means depending on the active theme.

To achieve this I made small wrappers for these functions to use style names (like 'button_background') instead of a color/font in Style.lua:

• SetDrawColor() -> SetDrawStyle()
• DrawString() -> StyledDrawString()
• DrawStringWidth() -> StyledDrawStringWidth()
• DrawStringCursorIndex() -> StyledDrawStringCursorIndex()

I made 2 seperate themes to demonstrate the change:

• Classic, to stay as close to the previous look as possible
• Dark, the way I personally like it (inspired by the poe2 trade site)

Note: I went through the draw calls and changed them by hand. I did not use AI for any changes to existing code.

After screenshots:

Here are some screenshots of the same views with both themes

Options

Configuration

Tree

Items

Calcs