[Fix] update backend cuda

Context

This MR is dedicated to handle two updates:

• getAvailableImplSpecs now returns std::vector<ImplSpec> instead of std::set<ImplSpec>.
• Add supports only 2 inputs

Modified files

• Test_AddImpl.cpp, Update Add unit tests to handle only 2 inputs;
• All Operators Impls headers, update getAvailableImplSpecs returned type;

TODO

• getAvailableImplSpecs Fix
• Add tests Fix