Convert remaining ScopedDbServices to new Mongo API

[kingzacko1]

Description

• Refactor remaining ScopedDbService classes and their corresponding test classes.
• Remove now unused ScopedDbService class and corresponding test classes.

/nocl not user facing /prd Graylog2/graylog-plugin-enterprise#7357

Motivation and Context

Migrating DB services to use new Mongo API

How Has This Been Tested?

local dev env. still working on testing everything but wanted to open this up so others could help since it touches quite a bit of code.

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [X] Refactoring (non-breaking change)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.