Cloudpub

- Revert Azure: always overwrite images on draft
- Update the default schema version on Azure Session
- Fix typo in models.ms_azure.CorePricing

- Azure: always overwrite images on draft

- Fix Azure bug with deprecated Disk Versions

AWS:
- Adds restricting versions

Azure:

- Change disk version to be mandatory
- Refactor the `publish` method
- Fix bad converter for Government Certification
- Fix the friendly_name on OSDetails for Azure
- Fix code smells

AWS:

- Fix timeout security issue
- Update timeout attempts/ intervals

This is the first version of `cloudpub`, capable of:

- Associating and publishing a VHD image on Azure through the Product Ingestion API.
- Associating and publishing an AMI on AWS through Boto3.