Introducing NamedEnum to parse enum value as string names.

Add support for parsing enum definition from enum value to string as
per the enum class definition.  Including the parsing for enum value zero,
to be able to use enum name parsing for all enum class include value of 0.

Bug: 160010896
Test: atest inputflinger, atest libinput_tests
Change-Id: I717fefd46eddf49cea1ba69429bdd6c856e6bc45