Support `google-java-format --skip-javadoc-formatting`?

[kevinb9n]

Just noticed that this command-line option doesn't seem to be supported by GoogleJavaFormatConfig.

google-java-format is of course very stingy with options, but does allow some behaviors to be switched on or off, like this.

Should this be handled like #929 - is there a similar rationale?

[nedtwigg]

A PR along the lines of #929 is very welcome :) Optionally, you might want to also do

• Use custom source sets and compile-only dependencies instead of reflection #524

while you're at it. Feel free to drop support for older GJF versions if you need to, but try to stay as compatible as possible.