Change auto-registration in 2.10 to provide "new" (JavaTimeModule) instead of legacy module

Up until 2.9, automatic Module registration using `ObjectMapper.findAndRegisterModules()` (and alternatives) has found the "old" module (`JSR310Module`) instead of newer `JavaTimeModule`. This was due to backwards compatibility concerns.
But at this point it seems less likely there are issues regarding setting and since 3.0 will only provide newer module, let's change defaults in 2.10.
