Add SharedConfigState opt to AWS session for assume role support

[raphapr]

- What I did

Enabled support for assuming roles to AWS session. Adding SharedConfigState to session options will instruct the SDK to enable support for assuming roles from shared config file. By default without this opt set the SDK will not be able to assume roles.

- How I did it

Added SharedConfigState opt to aws.Session

- How to verify it

Build an image i.e examples/aws.yml then load a AWS_PROFILE with assumed role. Then push the image to AWS. The credentials profile for assuming a role should be as described in AWS documentation.

- Description for the changelog

• Add the ability of assuming roles when pushing the image to AWS

- A picture of a cute animal

"Please"