Permit whatwg URLs for requests

[yawkat]

This PR changes the URL parsing a bit.

• Introduce a fast path for "boring" valid relative URLs. This is always enabled and lets us skip the expensive URI parsing with default settings.
• Add a config option that escapes certain characters that are valid in whatwg URLs (e.g. []|, browsers will happily send these) but invalid in java.net.URI. This allows those characters to be handled normally by the server.
• Remove the option to disable URI validation. The normal path should be fast enough now, and for those that need the whatwg-only characters, there's the new escape config option.

There's also a giant WhatwgParser class in the tests that I implemented while researching a while ago. I don't plan to move it to production code atm, but it remains useful for tests.

[sonarqubecloud]

Quality Gate failed

Failed conditions
55.8% Coverage on New Code (required ≥ 70%)

See analysis details on SonarQube Cloud

[yawkat]

i might have to move this to micronaut-router for use there, putting this into draft for now.