In a regex, `.` means any character, so the default exclude list will
actually exclude more than intended (any path containing `.serverless`
for example).
Instead, use `String#indexOf()`
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.
