BED-5532 - PostgreSQL Batch Update

[zinic]

Description

DRY cleanup and refactors alongside a change to batch graph DB operation behavior for the PG driver.

Motivation and Context

Historically the batch operation in dawgs would rotate transactions. This has the effect of materializing results in each batch to observers throughout the duration of the batch. In this way, ingest and post-processing were never meant to be at-once transactions.

This change updates the PG driver to not spin up a transaction for batch operations.

How Has This Been Tested?

Existing tests pass.

Types of changes

• Chore (a change that does not modify the application functionality)
• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have met the contributing prerequisites
  • Assigned myself to this PR
  • Added the appropriate labels
  • Associated an issue: Issues and Pull Requests README #672
  • Read the Contributing guide: https://github.com/SpecterOps/BloodHound/wiki/Contributing
• I have ensured that related documentation is up-to-date
  • Open API docs
  • Code comments (GoDocs / JSDocs)
• I have followed proper test practices
  • Added/updated tests to cover my changes
  • All new and existing tests passed

[superlinkx]

LGTM!