Update the hook order because the functions need the .zip file in their resource
definition. Furthermore the zipping process / writing it to disc was optimized.
The ".serverless" directory is also added to the "default exclude array" so that it's not
considered during packaging.
Each plugin now has a README.md file in it's root folder. The docs/README.md file
links to each plugins index folder so that the user can directly see the plugins folder structure
and the corresponding README.md file at once. This makes understanding the plugin way easier.
