Remove remaining files after Latest News removal

[damianstasik]

Description

Since we no longer have the section we can simplify the config by removing the custom blog plugin and all remaining files.

Motivation and Context

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [ ] My change depends on a change in the main opentofu repository.