Moar changes on Autofill samples.

- Renamed HeuristicsService to DebugService.
- Removed multi-steps support from MyService (it was broken anyways)
- Created a new simple, temporary service to handle multi-step logins.
- Added anti-pattern example for login without hints.
- Added anti-pattern example for autocomplete without using autofill callbacks.
- Added anti-pattern example for multi-step login using activities.
- Added edge-case example for custom theme that changes autofilled text.

Bug: 114236837
Test: manual verification

Change-Id: I7f0f63c090507c247f16eda0075cc20e6dc35139