EOS-wnc improvements

[branko-blagojevic]

• CONSOLE: Fix inoperative json command
• WNC: Code refactoring; Implemented support for JSON output format
• WNC: Request but do not require client's SSL files over gRPC

[esindril]

Thanks for the pull request, Branko! This is now merged in the eos5 branch and below you have reference to the latest commit: https://gitlab.cern.ch/dss/eos/-/commit/00a4b6238c77e709a2e77d7f62ce2dd5af7e7189

This functionality will be included in EOS 5.0.24.