Exclude folders/files from package when packing

[Splitwirez]

It could be nice to be able to exclude certain folders and/or files from the output package when packing a project. This could be useful in scenarios where, for example, a mod is open-sourced onto a GitHub repository - this would allow for the .git, .gitattributes, .gitignore, LICENCE, README.md files and such to be excluded from the output package while still being present in the project folder for their intended purpose.