Move contributors.tex to the main folder

[facusapienza21]

I had created a separate contributors.tex file inside tex so people can add their names as they contribute to the project in a separate file to the rest of the text. I think it will be a good idea to have this text file in the home directory of the repository to give it move visibility. If we want to do this, we just need to add some extra commands in the Makefile so it moves the contributor.tex file back to the tex folder and then gets rid of it after compilation.