Add copy-all-files-in-directory version of builder.AddCopy

[peace-maker]

Instead of having to manually list all files in a directory, allow to just use a wildcard to add all files. This would cleanup SourceMod's PackageScript.

https://github.com/alliedmodders/sourcemod/blob/e6129ab2d9bfadccd05567e4e542d1c397ba8cc5/tools/buildbot/PackageHelpers#L49-L62