AWS | storage: big refactor

Logics have been centralised:

* region to hostname
* url generation
* signature
* chaning scheme also changes the port

During the process a couple of inconsistencies have also
been fixed.

Known limitations:

When using the @endpoint with a custom port you need to specify the port
when using get_object_http_url or get_object_https_url.

When using bucket names that contain dots outside of us-east-1 make sure to
access it with the same region in your AWS::Storage.