chore(nvim): Some clean up

- Start splitting plugins to their own files
- Config should be loaded first
- Config for plugins should be handled by lazy.nvim

.config/nvim/lua/null/config.lua

@@ -8,5 +8,3 @@ o.relativenumber = true
 
 g.mapleader = " "
 g.guifont = { "Sarasa UI J", ":h16" }
-
-require("oil").setup()