add dev mode where warnings don't fail the test

[zeitlinger]

This provides a better dev experience:

gradle test -Ddev=true -x spotlessCheck -x checkstyleMain --tests '*JvmMongo*'

If this idea is accepted, I'll document it in CONTRIBUTING.md

[trask]

This provides a better dev experience

can you explain a bit more why (or what specific use case you're thinking of that this improves)? thanks

[zeitlinger]

This provides a better dev experience

can you explain a bit more why (or what specific use case you're thinking of that this improves)? thanks

it's annoying to be bothered by warnings when I want a try something out, which happens quite often

[trask]

it's annoying to be bothered by warnings when I want a try something out, which happens quite often

oh sorry, I misread the PR title, I totally agree this is annoying