chore(knex): adds comments around config choices. No code changes

[iainsproat]

Description & motivation

Provides more commentary around the choice of configuration values for Tarn. Also provides commentary as to why some default values should not be amended.

Changes:

To-do before merge:

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.
• I have added appropriate tests.
• I have updated or added relevant documentation.

References

[github-actions]

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