feat: adds image tests to CI

[jpower432]

Description

• Pre-push image scanning
• Adds optional E2E tests to run after push. Enabled by default with the workflow_dispatch trigger.

Rationale

The workflow dispatch trigger is used on the publish.yml to allow for changes to be validated in the published image.
E2E tests can be run as the first step to check for regressions before conducting further validation.

Blocked by #91
Blocked by #87

Type of change

• New feature (non-breaking change which adds functionality)

How has this been tested?

• Validated here https://github.com/jpower432/trestle-bot/actions/runs/7093744197

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[beatrizmcouto]

Reviewed during paired code review on Dec 6