Idea: path for Error Prone plugins separate from processor path

Recently, we've run into a couple of NullAway issues due to difficulties caused by passing NullAway on the annotation processor path:

https://github.com/uber/NullAway/issues/75 (Kotlin gradle plugins + kapt take over the processor path)
https://github.com/uber/NullAway/issues/118 (Issue with maven-compiler-plugin and processor path)

Internally we've also had Lombok compatibility issues due to this. It seems it might be useful to be able to pass in a "plugin path" of jars separate from the annotation processor path, such that Error Prone would look for plugins in this path if it is present. This way, these compatibility issues with the processor path could be avoided.

Thoughts? I'm willing to do some of the legwork on this if folks think it's a good idea.