* update comparisiofiles to use const ref param
* introduce conversion layer test definitions
* adapt old tests to the new format
* remove old duplicated conversion tests
* fix "convertion" typo to "conversion"
* fix style issues and abandon unnecessary changes
* fix include order
* update remaining conversion tests to use introduced class
* fix gpu class test naming
* bring back convert.hpp and convert_like.hpp files
* bring back convert.hppcppd convert_like.cpp files
* bring back single_layer_tests/convert.hpp file
* add missing copyright info
* fix issue with braces initiator for conversion types
* add missing convert_like tests
* add deprecated code macros
* update deprecated code macro message
* add missing space in deprecated code macro message
* update skip ConvertLike tests ticket
* update deprecated code to use IE macros
* update remaining ngraph_deprecated macros to use IE macros