Cleanup: rawtypes, unchecked, NullAway, errorprone and some inspections

[TWiStErRob]

The goal was 0 compile-time warnings, so new ones can be noticed easily and fixed.

[JakeWharton]

Can you split this up? Its individual pieces are far more likely to land and it's easier to discuss them in isolation then when all grouped together.

[TWiStErRob]

sure

[TWiStErRob]

Closing as split:

• e10f958e Remove residue from 4c9d7a0
  • already done in https://github.com/JakeWharton/dagger-reflect/pull/29/files#diff-6f0b84cc3cf4faa16145ef4af80a80daR28
• 641288a5 Clean up unchecked and rawtypes warnings
  • moved to Clean up build warnings #35
• 103d9d60 use broader types
  • moved to Fix some inspections #37
• 5a62404a don't hide valid inspections
  • moved to Fix some inspections #37
• 3f53f131 Fix errorprone UndefinedEquals violations
  • moved to Fix errorprone UndefinedEquals violations #34
• c0891804 Fix NullAway warnings and add @Binds and @Provides @Nullable tests
  • NullAway was fixed during Model optional keys during binding linking #26
  • tests moved to Add tests for @Provides @Nullable and @Binds @Nullable #36