common: Deprecate NonNullUtils#equalsNullable

common: Deprecate NonNullUtils#equalsNullable

java.util.Objects#equals does the same thing and provides
some advantages:

1- It is tested/supported by Oracle
2- It is almost binary compatible upon inspecting the code
3- It is more likely that the compiler will receive
   optimizations for their libs than some that are
   _almost_ binary equivalent.
4- It is industry standard, people can understand the code
   better.

Change-Id: Ica0371deee5876f4cbf42f2b6b521d07a8010067
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/76919
Reviewed-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Tested-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Reviewed-by: Hudson CI