improve README.md and created an install script

[Fabricio-191]

Please before merging the pull request check if everything in the documentation is fine.

A friend of mine tried to install this, but he does not have any idea of git, that is why i made the script

And i have a question, in the .patch all the path points to the com.unity.render-pipelines.universal folder, but in my friend unity project the folder has a version at the end, like: [email protected] (was incompatible cause the version) and the only place i find that folder, was in library/PackageCache/.

So what the script does is go from the root of the unity project to library/PackageCache/ folder, then searches for all the folders that start with com.unity.render-pipelines.universal and temporarily renames them while applying the patch.

If there is something wrong with this behavior, tell me, so I can fix it. because the truth is, i hardly know unity and therefore I do not know if I apply the patch well.