Deprecate JavaPoet interop

[Egorand]

JavaPoet is deprecate, so we probably want to deprecate the interop module as well. Questions:

• Should we stop releasing new versions?
• Should we delete the code?

[ZacSweers]

Could we ask the fork/successor to move it to their development if they're interested?

[JakeWharton]

Remove + inform the fork is my vote.