[E2E] Assert on database state in E2E tests

[dylanlott]

Objective

The current E2E tests are fire-and-forget broadcast or send messages. A component is needed to assert on the state of each validator's database.

Origin Document

E2E Testing Framework

Goals

• Allow for querying each validator's PostgreSQL database to be queried and asserted in a step definition.
• Investigate if a similar approach can be used for each validator's Badger database.

Deliverable

• A step definition that can query any validator's database with any arbitrary SQL statement and args.

Non-goals / Non-deliverables

• Nongoal prop: the agreed upon repository structure #1
• Nongoal Version Number #2
• ...

General issue deliverables

• Update the appropriate CHANGELOG(s)
• Update any relevant local/global README(s)
• Update relevant source code tree explanations
• Add or update any relevant or supporting mermaid diagrams

Testing Methodology

• Task specific tests or benchmarks: make ...
• New tests or benchmarks: make ...
• All tests: make test_all
• LocalNet: verify a LocalNet is still functioning correctly by following the instructions at docs/development/README.md
• k8s LocalNet: verify a k8s LocalNet is still functioning correctly by following the instructions here

---

Creator: [@dylanlott ]

[Olshansk]

Are we pretty much going to enable "SQL injections" during local development? I like the idea as it'll make testing easier, but we should probably make sure to use a test/dev build tag to guarantee it doesn't go into production.

[dylanlott]

I'm not exactly sure of the implementation details yet of course, but I can see that being one way this is solved. To that point, the e2e package does already use build tags by convention, so I would first point there for addressing the security concerns.