Update branding to Microsoft Azure Storage

[jeffpaul]

Is your enhancement related to a problem? Please describe. The naming (but not slug) for this project has been updated to "Microsoft Azure Storage for WordPress", but there are still some stray comments and non-code items in this repo that still reference "Windows Azure" instead of "Microsoft Azure".

Describe the solution you'd like

• [ ] update comments and non-code items to "Microsoft Azure"
• [ ] update banner/icon as necessary and with provided assets from Microsoft

Designs TBD if banner/icon could/should be updated

Describe alternatives you've considered n/a

Additional context n/a