Add `shouldLog` to better control logging spam

[buttilda]

Currently, adding the problem-spring-web package will result in any exception that isn't explicitly handled to be logged in full (stack trace and all) and with no obvious way to stop it. While this may seem like a good idea, a common trope of handling expected errors is to throw a Problem or a ResponseStatusException after some validation step. For example:

@GetMapping("/route")
fun myRoute(@RequestHeader("X-Custom-Header") customHeader: String) {
  if (customHeader != "fixed-value") {
    throw ResponseStatusException(HttpStatus.BAD_REQUEST, "Invalid X-Custom-Header")
  }

  // happy path
}

Doing so while having problem-spring-web active will result in the hole stack-trace of ResponseStatusException to be logged.

This behaviour can be stopped by overriding the log(...) method in ProblemHandling but I'd argue that's not very obvious nor very clean. Thus, my proposed solution is adding a shouldLog(...) function which can then be overriden.

I chose to add the default behaviour of not logging ResponseStatusException or Problem as I believe those are pretty commonly thrown in situations where having the whole stack-trace printed isn't needed. Though I can agree with the argument that this would be a backwards incompatible change and therefore don't feel very strongly about it. Let me know and I can remove it and leave the implementation as return true; instead.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.