Split InputReader into multiple files

This CL:
1) Moves commonly used macros and shared definitions into Macros.h,
which is included as the first #include statement in the files that
require it.
2) Creates InputReaderContext.h and moves the context definition outside
the InputReader.h file.
3) Moves InputDevice, InputMapper, StylusState, and all of the
individual InputMappers into their own header and cpp file combinations.
4) Moves all Accumulator classes that are shared between multiple
InputMappers into their own header and cpp file combinations. The
definitions of Accumulators that are unique to a mapper are kept in the
header file of the mapper.
5) Moves constants and static methods that were shared between the
TouchInputMapper and CursorInputMapper to
TouchCursorInputMapperCommon.h.
6) Creates an 'include' directory, as well as a header library build rule,
to hold all the header files required by InputReader_test.cpp.
7) Runs clang-format on the newly create files to fix formatting
inconsistencies.

Bug: 140139676
Test: atest inputflinger_tests
Test: Touch, keyboard, trackpad, and mouse works on crosshatch
Change-Id: Ib1ac871c7f4199729bf6d0e6a53ed907af318986
Merged-In: Ib1ac871c7f4199729bf6d0e6a53ed907af318986