[Feature] Encapsulate config logic (#1338)

* Define core/builtins, streamline status_color interface

* Encapsulate configuration in its own module

* Add fallback to lv-config.lua

* Rectify settings loading order to allow overriding vim options

* Move default-config into config/ module

* replace uv.fs_stat with utils.is_file

lua/core/builtins/init.lua

@@ -0,0 +1,29 @@
+local M = {}
+
+local builtins = {
+  "keymappings",
+  "core.which-key",
+  "core.gitsigns",
+  "core.compe",
+  "core.dashboard",
+  "core.dap",
+  "core.terminal",
+  "core.telescope",
+  "core.treesitter",
+  "core.nvimtree",
+  "core.project",
+  "core.bufferline",
+  "core.autopairs",
+  "core.comment",
+  "core.lspinstall",
+  "core.lualine",
+}
+
+function M.config(config)
+  for _, builtin_path in ipairs(builtins) do
+    local builtin = require(builtin_path)
+    builtin.config(config)
+  end
+end
+
+return M