erp5_forge: Automatically import a zip package into erp5.

This commit mainly serve as an example.

Suppose we need to update the ckeditor. We can download the package zipfile. Then upload the zipfile in ForgeModule_importZipFileDialog. The script will automatically extract the files in it. And update or create(if not exist) files in erp5.

Please read the code and the comment in ForgeModule_importPackageFromZipFile.py before using it. And add your modification if needed.