Rename and move classses

Rename MagnificationController and move the classess about
magnification to magnification package.

Test: FullScreenMagnificationGestureHandlerTest
MagnificationControllerTest.java
AbstractAccessibilityServiceConnectionTest
Bug: 160557771

Change-Id: I8d1e4fced6874e7dcac13dd5e9fafc6279b4ac34
12 files changed