📈 Add rule and sample app around clean testing best practices

[danielmackay]

Currently with integration testing we are using both Respawn and Test Containers to create and reset our databases.

### Tasks
- [ ] Create a rule that provides guidance on when to use respawn vs a new test container
- [ ] The rule should take performance into account
- [ ] Create a sample repo to demonstrate the approach
- [ ] Add the sample repo to the awesome-ca repo