feat: Do not depend on user config | Fix merging of configs

because it is a user config, so our config shoudn't break even we if dont have it

use our own table merge function

move loading config to a function

use a global variable to store the config, so no need to call the table function everytime

lua/plugins/chadsheet.lua

@@ -4,7 +4,7 @@ if not present then
    return
 end
 
-local mappings = require("chadrc").mappings
+local mappings = require("utils").load_config().mappings
 
 -- add user mappings to the cheetsheet
 for section, data in pairs(mappings) do