Unity 2017 menu system with moddable content

I need you to develop some software for me. I would like this software to be developed for Windows, Linux, and Mac. Setup in unity a menu system that uses buttons from material file loaded at start of program. And start up at the program it will look at the mod list and load a list of files the need to be loaded in. Primary data directory then mods and Order if a mod has a file that replaces the previous mods file for materials texture it will just overwrite the previous one. If there is data it will load the First Data file and then I'm n at the end the data from the mods or it will overwrite the mold file. If a mod is loaded with an override file it will havea setting to allow or not allow any following mods add to its file. There will be a localized file that all of the text is drawn from. This will allow other languages