Open source GoodTime checks

### Context

Google projects like Guava have `@SuppressWarnings("GoodTime")` in various places ([github search](https://github.com/search?q=repo%3Agoogle%2Fguava%20GoodTime&type=code), [sourcegraph search](https://sourcegraph.com/search?q=context:global+%40SuppressWarnings%28%22GoodTime%22%29+r:github.com/google/&patternType=keyword&sm=0)).

As I understand it from my time at Google, the GoodTime checks make working with time better in Java, and help devs avoid footguns. Things like:
- prefer using `java.time` over older libraries like Joda
- prefer using strongly typed `Instant` and `Duration` over weakly typed `int millis` or `int epochSeconds`
- use TimeSource instead of `Instant.now()` to allow testing with an externally-supplied fake clock/source
- many others I'm sure

### Issue

Are these GoodTime checks something that might be open sourced? I remember them fondly and wish they were running on my current codebases!