Combine webrtc/api/java/android and webrtc/api/java/src.

It used to be that there was a Java api for devices not running Android
but that is no longer the case. I combined the directories and made
the folder structure chromium style.

BUG=webrtc:6067
R=magjed@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/2111823002 .

Cr-Original-Commit-Position: refs/heads/master@{#13356}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: ceefe20dd65387d83059d9fc1ce84842650ed5e2
73 files changed