Feature: Update Blogs to match current SuperMQ refactor

[Musilah]

Is your feature request related to a problem? Please describe.

Some blogs are currently using outdated implementations from earlier versions of SuperMQ, relying on deprecated services and authorization methods. These should be updated to align with the latest version.

Describe the feature you are requesting, as well as the possible use case(s) for it.

Here are the files with the issue:

• Kratos Blog: Kratos still uses the clients implementation for both Users and Things
• OAuth Blog : This still uses the old OAuth implementations as well the using Clients Service
• User Guide Blog: This still uses things service as well as old auth

These should be reviewed and updated to ensure compatibility with the current iteration of SuperMQ.

Indicate the importance of this feature to you.

Must-have

Anything else?

No response