BED-4963: Clean Up and Tighten Enforcement of Linters

[superlinkx]

Description

Describe your changes in detail

This PR is composed of several separate commits for different fixes and improvements to code that was showing up in our linter warnings.

• Removal of our own errors package, leading to a refactor that switches all usages to the stdlib errors package
• Clean up of unused code, incorrect function signatures, and other minor fixups recommended by the linter
• Two problematic deprecations were added to our ignore list for now, with tickets generated to cover properly resolving them in the future
• Now that there were no warnings, upgraded all existing warn level issues to error level
• Enabled errcheck as our new warning to start the long process of resolving errcheck issues, before promoting it to error level (no other linters are being turned on yet since errcheck is going to be a very large undertaking on its own, we'll evaluate other useful linter rules after errcheck graduates)

Motivation and Context

This PR addresses: BED-4963

Why is this change required? What problem does it solve?

Our linter warnings were piling up, and they're not super helpful to devs when there's that many. This PR aims to resolve existing warnings (or add exclusions until proper fixes can be evaluated), graduate all existing warnings to error level events (requiring devs to resolve or add exclusions before merging), and enable the next linter rule in our quest for continuous improvement.

How Has This Been Tested?

Please describe in detail how you tested your changes.
Include details of your testing environment, and the tests you ran to
see how your change affects other areas of the code, etc.

All code builds and tests fine after the changes. No logical changes should exist outside of wiring up an unused part of the OpenCypher compiler.

Types of changes

• Chore (a change that does not modify the application functionality)

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