feat: added color_overrides to settings

the `g:catppuccin_override_colors` variable was removed in favour of a
setting in the user's Catppuccin conf. This commit also added the
ability to change individual colors per palette and also apply changes
to all of them.

lua/catppuccin/config.lua

@@ -71,6 +71,7 @@ config.options = {
 		telekasten = true,
 		symbols_outline = true,
 	},
+	color_overrides = {}
 }
 
 function config.set_options(opts)

lua/catppuccin/core/palettes/init.lua

@@ -1,5 +1,7 @@
 local M = {}
 
+local cnf = require("catppuccin.config").options
+
 function M.get_palette()
 	local flvr = vim.g.catppuccin_flavour
 
@@ -8,8 +10,10 @@ function M.get_palette()
 		palette = require("catppuccin.core.palettes." .. flvr)
 	end
 
-	if type(vim.g.catppuccin_override_colors) == "table" then
-		for k, v in pairs(vim.g.catppuccin_override_colors) do
+	if type(cnf.color_overrides) == "table" then
+		for _, pal in pairs({"all", flvr}) do
+			if cnf.color_overrides[pal] ~= nil then
+				for k, v in pairs(cnf.color_overrides[pal]) do
 					if palette[k] then
 						palette[k] = v
 					else
@@ -21,6 +25,8 @@ function M.get_palette()
 					end
 				end
 			end
+		end
+	end
 
 	return palette
 end