Handles uploading a package from your computer...

• Uses the Packages language and template files
• Part of the manage_packages adminIndex
• Uses the package template layer and downloaded sub-template
• Dies with an error if the file isn't a ZIP or tar.gz archive
• Attempts to chmod the package
• Deletes the file if it isn't a package
• Loads up all appropriate info for the file (filename, install link, etc.)
• Will not rename the file if it already exists.